Ask me a Question

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317 thoughts on “Ask me a Question

  1. Hi dr chemical, I accidentally over sprayed bam oven cleaner on to the grass whilst cleaning the racks outside (a lot of over spray) how can I make this patch of grass safe for animals I hosed it down will this make a difference?
    Tia

    • If you hosed it off then it’s fine. And anyway it’s unstable in air and quickly degrades to harmless compounds

  2. Recently purchased jeans have a strong chemical small, similar to diesel. Normal wash cycle has not removed it. Any suggestions. Cheers Jenny

    • Hang it outside in fresh air for a couple of weeks – there is no substitute for fresh air for this. If it is diesel, or anything like it, get some Kenco degreaser from bunnings and use it as a laundry prewash

    • Oven cleaner. Spray on and wipe off. Alternatively put some metho in a generic spray bottle and that’ll work well too

  3. Hi Dr. Chemical
    A Liqudambar tree on my neighbour’s property is sending roots under my concrete driveway that travel 10 metres to my garage and under the house, lifting and cracking the concrete in the process. I’ve tried weed killers to stop the roots to no effect. Any ideas?

    • Yep. Go to the hardware store and buy the strongest solution of glyphosate you can get. I think yates sell a 1L bottle for about $12 that has a concentration of 360g/L. Take no notice of the brand – the glyphosate in Roundup is exactly the same as the glyphosate in every other brand. Then get a wood drill and drill as big as a hole as deep as you can in the root. Then tip the glyphosate in straight away (within a couple of minutes) before the pores close upon exposure to the air. More holes is better. It will begin to kill the tree in a couple of weeks. And no one will be any the wiser….m And there’s no way to kill the roots without killing the tree.

  4. Hi Dr Chemical.
    Yesterday I was sneaking a Maccas frozen raspberry into the movies inside my ligt tan leather handbag and tripped on the step, spilling the drink inside and on the outside of my bag. Gaaaaah!!
    I have carefully washed the fabric lining, but need some help on how to remove the (now dried) stains from the outside of my bag. Please help!
    Jen

  5. Recently my son and I used a heavily diluted mixture of muriactic acid to scrub his basement concrete walls – we waited about 3 hours and the painted the concrete with a waterproof paint.

    I neglected to wash down the wall before painting.

    Must I remove the paint to wash the walls and then paint again ?

  6. Hi I have a pinkish dust all over my bath after removing the grout and don’t know what it is, I’m hoping I haven’t hit the villa board or something .

  7. Hi Dr Chemical,

    Can you tell me how to remove a rust stain from the toilet bowl please.

    One of my sons dropped a round battery into the toilet which sat there for a couple of days before I found it and removed it, but it has left a rust stain that is under the water line.

    Thank you
    Naomi

    • Tip half a litre of hydrochloric acid into it and you should see it dissolve after a few minutes. Then flush several times to flush it all away. Or use some wet and dry abrasive paper (with a glove) – it should rub off pretty easily

  8. Hi Dr Chemical, How do i get rid of the urine smell on a carpet mat ? Had it cleaned twice ( carpet cleaners) and the smell is still there.. can’t see what its made of but it says professional dry cleaning recommend. Sure this will cost a fortune. Can you please advise me what to try. Can’t see stains but strong smell still.

    • Use vinegar. It will neutralise the amines that cause the smell, and create its own individual pleaseant smell. But if it’s on a mat the best option is to put it outside in fresh air for a week or two. The smell will eventually evaporate

  9. Electro Chemically Activated water is apparently environmentally friendly and is a great disinfectant, that is Hypochlorous Acid. Why is this a “green” product and normal Chlorine is not? If you dissolve Chlorine it will also form Hypochlorous acid under the correct pH. Is that also environmentally friendly.
    It confuses me, can you please help.
    Thank you
    Kind regards

    • By “electrochemically activated water” you are apparently referring to seawater that has been through an electrochemical cell where the chloride in salt water is converted to chlorine. This will convert to hypochlorous acid at pH 8.2 to 8.5 which is the species that reacts with nasties in the water, which is what you want. Bleach (sodium or calcium hypochlorite) works by exactly the same mechanism, also producing hypochlorous acid in this pH range. So I’m not sure what you intend by “environmentally friendly” but there is no difference between the two. In both cases the chlorine compounds are unstable and will eventually degrade in light to salt and water

  10. Good afternoon,
    Could you please suggest how to remove a large amount of tannin stains from outdoor off-white colour ceramic floor tiles? I’m not sure what type of timber has caused the staining.
    Thank you,
    Julie

  11. Hi Dr Chemical

    Can you please tell me how to remove the ink stain from white furniture? I had a catalog sitting on top of a white painted wooden cupboard and some oil or something leaked on it, don’t know how long it was sitting like that but the ink from the catalog has transferred to the paintwork, don’t know what to do or how to remove it. Please help!

  12. Hi Dr Chem,

    What product/s would you recommend for cleaning heavily watermarked pavers?
    Have already tried high pressure hose and water = nothing
    Hydro acid scrubbed in and then high pressure hose. Some shift in stain

    • You want caustic soda. Sprinkle flakes on, wet them with a minimum of water, then rub in with a stiff brush. HP cleaning would then bring it up a treat

  13. Hi Dr Chemical,
    I am finding it difficult to remove gecko poo from my cream rendered outside walls.
    It appears to stain the walls and too much pressure affects the render. I have tried detergent and hot water with a soft scrubbing brush but it doesn’t remove the stains.
    Thank you

  14. Hi Dr chemical,

    Could you explain why nervous sweating smells so much worse than normal sweating? For example, when my partner sweats in his t-shirt due to nervousness, rather than being hot, the smell is very strong, acrid almost and won’t come out in the wash. Where as any other sweating will easily come clean in a normal wash.

    • That’s above my pay grade, I’m afraid. It’s entirely possible that a different smell is generated, but I don’t know why. But it shouldn’t effect washability. What temperature do you wash at and what brand of detergent do you use?

  15. Hi, I have a mustard yellow coloured leather brand new banquette (bench seat) in my new kitchen. It already has some stains from the builders!! I know one of the stains is from kitchen detergent, not sure about the rest. Please advise the safest method to use without risking doing more damage. Many thanks – I have asked Shannon but was dubious about the reply. She suggested the method would depend on whether the leather was a type that absorbed water or not.

    • A general approach to cleaning leather, without knowing exactly what the stains are, is to use Dubbin. It’s generally available from supermarkets or hardware stores, and will help rub out most stains. But if it’s mustard yellow, it means that it has been dyed somehow, and it’s possible that the stains have actually reacted with the dye somehow, in which case there’s not much you can do.

    • Do you mean remove it from your clothes? You don’t need to – hydrogen peroxide is unstable and decomposes with exposure to light into water and oxygen. By the time it gets to the shop where you bought it, it will all be gone

  16. Hi, love this column, lots of good info. What can you suggest for cleaning and then protecting the white seats (vinyl) I think on our boat.
    Also there is a musty smell in the carpet, what is best to clear it up. I have bicarbonate soda sitting around to absorb the smell, but it’s still there.
    Thanks heaps.

    • You can’t beat Mr Sheen for the seats. For the carpet, there is simply no substitute for air, if it’s the carpet in your boat and it can be removed. If it can’t then heat, and lots of it. Put a fan heater in there and close the doors, but leave a window cracked open so the moisture can escape. With enough time it will evaporate and the smell dissipate

  17. we have a smc fibreglass shower base that we use a enviromentally friendly cleaner on we make which is white vinegar,epsom salts and eucalyptus oil. and the shower base is turning a vivid blue any ideas to return it to white again.??

    • Use a non-caustic oven cleaner on it. I wouldn’t be using eucalyptus oil on fibreglass – it’s porous and will soak in. For ongoing cleaning use any acidic bathroom cleaner (such as Ajax Spray and Wipe with Lactic acid)

  18. Hi Dr Chemical
    I am really hoping you can help me had a new linoleum (timber imitation) floor laid unfortunately we place a rubber dart mat down and have found the bitumen has left a yellowish stain on the Lino …..ruining our new floor
    Any advice is greatly appreciated
    Pauline

    • soak a rag in metho and sit it on there for a couple of hours – that should shift it. Failing that, try washing soda, used as a paste (add water to it) with a mild scourer

    • Use a stronger acidic bathroom cleaner (Ajax Spray and Wipe with lactic acid). If that doesn’t shift it, then the glass may have been etched by the soap scum, in which case there’s nothing you can do about it

  19. How do I rejuvenate the finish on exterior hard black plastic trim on my car? It has taken on a sperkly, chalky finish, like it is breaking down thanks to UV. It is also on my roof rack mounts and the windscreen wiper arms.

  20. A friend spilt plunger coffee on my heavy white linen tablecloth. I have soaked the stained area in cold water with some Sard Wonder Oxyplus, Power Stain remover, which has a eucalyptus smell. Can you suggest anything more effective and should I then machine wash it (Front loader, Omo Sensitive)?
    I heard you on Curtin 100.1 FM…. brilliant!
    Many thanks
    Merryl

    • The problem is the temperature. It needs to be about 40 deg for any of those products to work. Use some White King Stainlift. Spray it on, let it soak for a while, then wash at about 40 deg (warm on some machines, hot on others). 40 deg is the optimum temperature for the enzymes to work. If that doesn’t work, use it as a spot cleaner, rubbing it in with your fingers. Your fingers will create the right temperature to activate the enzymes

  21. Hi Dr Chemical,
    You are so helpful, I wish you lived next door!

    A couple of days ago we had a water leak coming in from our roof; the carpet (not sure if synthetic or wool) now has a large stain (the water in the bucket was slightly dirty yellow colour). It is now almost dry. Any suggestions to try and remove the stain? Or, should we just call the carpet cleaner. I notice from previous posts you refer to high pressure steam cleaning with high vacuum extraction; would this be suitable? Thanks, Frankie.

    • That should be pretty easy to get out with any of the off-the-shelf carpet foams. If you’re in Perth the best carpet cleaner I have found is Clean Underfoot. If elsewhere, and you need to get it professionally cleaned, don’t waste your money on anyone that doesn’t turn up with a van or truck with a big machine in the back and long hoses to get in your house. The portable units are a waste of money

  22. I have white quartz countertops in my bathroom. Around the faucets, I have a brown stain forming. I want to know what I can use to clean it without damaging the quartz. Traditional cleaners, acetone, and vinegar haven’t done the job. I watched a tutorial using Harpic to clean it but I’m unsure if this will hurt the quartz. What should I use?

    • Harpic won’t hurt it, and I can’t think of any common chemical that will. The brown staining is rust. Get some citric acid from the cooking aisle at the supermarket and use it in a paste (add some water to it) with a scourer. That should shift it but a bit of elbow grease may be required. If that doesn’t work, try some Oxalic acid, although I’m not sure where you’d get some from. Hardware stores used to sell it, but it’s getting a little hard to get these days. Or the other approach is use a mechanical approach (as opposed to chemical) and scrub it off with Ajax Powder Cleanser (or Bon Ami)

  23. My boyfriend cleaned the bathroom with a product that contains 80% citric acid. He didn’t realise it wasn’t suitable for our bathroom tiles as they are limestone. Now there are several white blotches. Can you advise a solution to reverse the colour back to the cream / egg shell colour?!

    • You can’t reverse it, but it will return with time as it ages. The white colour is simply the clean limestone with the outer (aged) coating removed. I’d suggest you do the whole surface and then let it yellow uniformly with time

  24. Hi Dr Chemical. How can I get water marks off my windows? They have been there a long time and are like water drops with a well defined white edge deposit. I have tried everything that I have been recommended (Ajax Spray n Wipe Bathroom, Orange Power, Hydrochloric Acid, CLR, natural cleaners) without any success. Any suggestions please?

  25. Hello Dr Chemical
    I hope you can advise me how to clean the plastic inflatable pool. I have removed the water but the bottom of the pool is covered with black/brown stuff!
    With thanks in anticipation

  26. Hi Dr Chemical – I have a linen/cotton blend dress which has a navy background with large white spots. I always hand wash the dress in lukewarm water but the navy dye bleeds into the white spots. I have put salt and vinegar in the water to stop the dye running but no joy. Any suggestions

    • If you use a premium brand (like OMO) they have antiredeposition agents that stop this happening. Or you can buy colour absorption swatches that you throw in with the wash that also work

  27. How do I remove a rust mark from a metal stud on my white denim shorts when they were left soaking in a bucket of water with Napisan for a couple of days?

    • Get some citric acid from the cooking aisle in the supermarket and rub it in as a paste and leave it to soak for a while. Rinse and rpt as required. If that doesn’t work get back to me and I’ll give you other options

  28. We have recently had a bathroom renovated. During the process of installing the new toilet a quantity of water leaked from around the base. I was told to leave it overnight so that the leak could be assessed. The problem was obviously sorted and job completed. However there remains (on dark grey/brown Cer Asia vitrified porcelain tiles) water marks where the liquid settled. The bathroom company don’t seem to be able, nor want to help. I have only attempted cleaning with Selleys Tile Clean but the marks remain. Can you suggest a solution? Thank you

  29. hi dr chemical, my male dog wees in one particular area under my patio,,,, it has now stained or discoloured the brown porous concrete pavers,,,, they have become almost white where he wees on them,,, have tried neat white vinegar,. left soaking for 10 minutes then hosed off,,,, with a pressure cleaner ,,,but when the pavers dry they still have the same faded white ish look about them,,thanx for your amazing remedies

    • Nothing you can do I’m afraid, once the colour has been stripped. To deter the dog I’ve heard that Vicks Vaporub can help. Leave an opened bottle in the area where he normally wees

  30. Thank you, thank you for your advice after I had yellow stains from a prewash spray on a caesarstone bench top . I sprayed with oven cleaner, had to wait a few minutes, wiped off, then like a miracle & I mean miracle, stain gone !!
    Am busy reading all your other hints now. Thank you again.

  31. Hi there, I just had a dark concrete path poured that meets a set of stairs made of Austral retaining wall blocks in a light sepia colour. Unfortunately, the concreters got some dark concrete on the block steps. Any ideas on how I get it off without ruining the blocks? Thanks.

    • You’d probably find that the adhesion of the cement to the block steps is pretty poor. Blast it with a heat gun, and you’ll probably find it’ll just chip off. You could help it by getting a small hammer and tapping on the dark patches – that should help break it up

    • The smells from vomit are caused by a class of chemicals called Volatile Fatty Acids (VFAs). The solution to it is a non-caustic oven cleaner. Spray it on, wait a minute or so, then wipe up with a wet rag or paper towel. Repeat as required and you should remove both the vomit and the smell

  32. HI Doc,

    I have a doctors surgery i clean that has vinyls flooring – quite old flooring id say from when it was built in the 70’s or something. There is discooluration on the floors – lighter and cleaner where not much traffic occurs, and darker dirtier looking in high traffic areas – have tried oven cleaner and ammonia but this hasn’t worked. can this old discolouration be removed?

    • I’m afraid not. The reason that vinyl flooring is cheaper is for this exact reason – it has poor chemical resilience and degrades with time. If you’ve tried ammonia then there’s nothing more you can do

  33. hi,
    I used a combination of dishwashing liquid & vinegar to clean a glass shower screen, however upon drying it has left a white film which I have found impossible to remove with a rang of commercial cleaners or neat vinegar. I haven’t tried any of the cream cleaners (JiF/ceramic cooktop cleaners) for fear of scratching the screen. Any suggestions ??

    • If you have tried something like Spray & Wipe Bathroom and it’s still there, then I’m afraid you’re out of options. Although it might look like a coating it’s actually the opposite – the glass has been etched. The only option you have is to attempt to fill in the cavities and cover it up. Use of Mr Sheen or automotive polish (with silicone) might help. Or there’s another option (that I haven’t tried). Go to Bunnings and tell them you want a product for sealing cement or bricks or slate. Some products say they have a “wet look”- if you painted one of these on the glass there’s a good chance it’d fill in the cavities and restore the clear look. It’s only an educated guess, but the chances are that it wouldn’t look any worse than it does now

  34. I have tent on my windows to keep the sun from fading my “carpet in my dining room, its beginning to look dusty what do i clean the windows with that wont harm the tent

  35. Hi , somebody spat on the side of my wife’s car, it has metallic paint , and i have tried everything to get spit stain of but nothing works any ideas,

    • Your best chance is metho, or maybe acetone (soak it for a little while). But it might not work – modern paints are very resilient.

  36. Our Silver Chain home help suggested oven cleaner for the black in grouting and occasional mould if the rubber mat has been down for a few days. Would love to try that but we have a bacterial sewerage system . Is the oven cleaner toxic so it will kill the bacteria.
    Also, Any easy way for an OLD lady to clean the oven?

  37. Hello I live in a house that is 20 years old and by the beach. The powder coating is now peeling off and I would like to repaint them as they are still in good condition however I am not sure of the best way to do this should I strip them right back and what sort of primer or chemical should I use to make sure the new paint job lasts the distance I have asked at a couple of paint shops but am getting conflicting advice. Much appreciate your help. Ana

  38. I’ve just read your global warming/carbon dioxide column at Principia Scientific. I asked a physicist friend (who is a global warming alarmist) to tell me what was wrong with your reasoning, and this is what he wrote: “His calculation is correct but he is doing the wrong calculation. He is doing a calculation of thermal conduction from the gas CO2 into the ocean. Where the real effect is that the atmosphere is trapping the infrared radiation and re-emitting it in all directions some of which goes back to the ground and the ocean. Water is a very good absorber of this infrared radiation.”

    This is all way out of my league, but I wonder if you could address what he has told me, and either re-validate your position, or poke a hole in his. Thank you!

    • No – he is right. That article was a far too simplistic approach to the issue. The mistake that I made was attempting to prove something. In general terms the position of the sceptic (which any scientist should be) is to ask others to substantiate their position by proof. Those who claim that manmade CO2 is heating the climate have not done so, and I don’t think they can

  39. I threw my girlfriend’s helium filled balloons in the shower and they went flat instantly they just sank to the floor.. what was it about the hot water that made the balloons seem to lose their helium or ability to float? As I wrote this post they started to slowly float back up are they zombie balloons? Seriously though I want to know

    • That’s a weird one. I need more details – when you say they “went flat” do you mean they visibly deflated? And then when they began to float again did they visibly expand in size?

  40. Hi, was wondering if you could tell me how to remove paint from a school shirt, not sure what paint was used at the school for their art class.

  41. Hi

    We have clear vinyl patio blinds that have become stained – robably from rainwater while rolled up – how can we clean them.

    thanks

  42. Hello Mark. I phoned you about a week ago when you were on Curtin Radio to ask how I could remove yellow stains from an old, but very good damask tablecloth and napkins. You suggested I use something that sounded like ‘BIZET’ liquid or powder. Could you tell me the correct spelling please, or product name if I have it completely wrong. No-one knew what I was talking about in the supermarket. It would be wonderful if the stains can be removed as it was my mother’s tablecloth, and I would love to be able to use it. Thank you for your time.

  43. I have a stain in my bathroom basin. The basin is white plastic or fibre glass and the stains looks like a cigarette burn but its not a burn but we can’t remove it. How can I remove it?

  44. How could I clean a red stain off my white leather Lounge? The red stain is from a red tinsel Christmas decoration that was pushed into the fold of my lounge (by one of my grandchildren).

  45. Mark,
    Your article on carbon dioxide and global warming is excellent just one correction. You state that ice caps melt in summer. Ice caps can’t melt in summer. Ocean ice around ice caps can melt but they are not ice caps. Ice caps are on land – Antarctica and Greenland -90% in Antarctica – caps are 1000s of meters thick in ice and average summer air temperature dont get above 0 degreesC. The 19million sq. km of floating ice around antarctica and the arctic ocean melt from beneath – from warm water currents. When they melt each year they return the water to the ocean without any change of volume to that the ice displaced.
    The highest ice at the South pole is a few meters different to the height of Mt Ararat where the Flood in Noah’s day rose. Coincidence?? I think not.

  46. Topic: Suboceanic volcanoes.

    You mentioned in a (great) article that CO2 could not heat the oceans water…in short, my question is..What about sun-oceanic volcanoes. I won’t elaborate as I’m certain you understand.

    Looking forward to your response

    • Sorry, I don’t know anything about those. My calculations were simple back-of-the-envelope calculations that show that, according to AGW theory, 0.4g of CO2 can heat a ton of water. I don’t think that’s anywhere near feasible. In particular, most people don’t understand the fundamental difference between a real greenhouse and the atmospheric greenhouse effect. In a real greenhouse, a highly dense material (glass) transfers heat to a much less dense material (air). In the atmosphere a material of low density (gas) transfers heat to a highly dense material (land or water). I therefore think it’s unfeasible

  47. Hi I just stumbled on to your page and i find it very interesting I found answers to problems that i have looking for quite awhile but now I have another —
    How can I keep moths off of the underside of a colorboand roof could i use metho or kero thank you

    • If anything, kero – the metho would evaporate too easily. But before you spray the kero on, try dissolving some naphthalene (mothballs) in it first – it should dissolve. This will give you a thin layer of naphthalene on the metal that should fix the problem

    • Bit hard to say without knowing what it is, but there is no substitute for air, and lot of it. Hang it outside in the shade somewhere and it should dissipate pretty quickly

  48. Hi
    How do you remove the hard build up of deodorant stains from a cotton tie dyed garment without removing the colour of the tie dye. I did a search on your site and nothing popped up.
    Thanking you.

    • If it’s the yellowing from aluminium based antipersperants, any acidic bathroom cleaner will work (Easy OFF BAM with sulphamic acid)

  49. Hi,
    Apologies if this has already been answered but I searched your site and couldn’t find any information. We use rainwater tank water to flush our toilets. One toilet, which has an integrated basin on top where you wash your hands with the water that is then used for the flush, has a continual brown tinge to the water in the bowl. The other does not (using the same tank water). We’ve tried a variety of liquid soaps and this doesn’t seem to make a difference. If you have any specific suggestions that would be great but I’m also interested in how to keep a toilet bowl relatively clean during a flush without using products like toilet duck etc or bleach type products. It seems citric acid can be quite powerful and wondered if you had any products that you could recommend for a: cleaning toilets in genera and b: keeping them clean? Thanks in advance! Heather

    • The brown tinge is iron. To remove it you’ll need hydrochloric aid. Harpic used to make a product that was thickened HCl but I don’t think it’s on the market anymore. The alternative is to scrub it with some wet and dry – that will work well. On an ongoing basis there is simply no alternative to the use of bleach to keep a toilet clean – the reason simply is that it is just so rich in the bacteria that promote biomass growth and iron staining

  50. Hello Dr Chemical,

    Can you recommend anything to use in wardrobes and drawers to protect clothes from clothes moths and silverfish? I want to avoid regular moth balls which contain naphthalene which I understand to be carcinogenic (please correct me if I am mistaken).

    Regards,
    Jovo.

    • Naphthalene is no longer thought to be carcinogenic. But one alternative is oil of cloves – I’ve had people say it keeps moths away. Or vicks vaporub – apparently the menthol is a pest repellant

  51. With washing soda being such a good cleaner along with some shine and protect properties, why is it not recommended for use on car paint.

    • I wouldn’t use it on car paint as it might scratch it. There are no issues chemically, but it’s fairly gritty and might scratch it, which is why its good for cleaning dishes and saucepans

  52. Hi, I have some golf balls that were retrieved from muddy water so the little dimples are dirty. Tried cleaning with standard detergent and water but it wont come off; any tips on how to clean the muck off the golf balls? Thanks, Frankie

  53. Hello Dr Chemical,

    We have bamboo floating floors in all rooms bar the bathrooms and laundry, 14mm click system with polyurethane finish. Can you advise the best way to clean it – the recommended hardwood floor cleaner was heavily scented and gives my husband and I a headache. We know you should only use a damp cloth/mop. Thanks so much!

  54. This is a question, can’t locate question section, anyway, my question is is there anything that can clean opaque garden solar panels or are they bin able when they go like this. Cheers Joy Grant

  55. We have gloss paint spots on new tiles on our bathroom floor and the tiles are not the gloss type of tile do you have any solution for removing please.

    • If you have a heat gun, blast them with that and they will just flake off. Or maybe a hair dryer at a pinch. Or soak a rag with metho and soak it on the tiles for half an hour. Or use Ajax Powder Cleanser (or Bon Ami). Any of those should work

  56. Dear Dr Chemical,

    What is your opinion on this latest eco-cleaning product to hit the market? Too good to be true, or plausible? https://www.ekoworxstore.com/

    “ekoWorx has been scientifically formulated with water, salts and ‘electrochemistry’. In lab tests, it has been proven to suspend and remove dirt and grease whilst killing bacteria. When released into the environment, ekoWorx reacts with carbon dioxide in the air to become completely inert.” Dr Leigh Aldous, Chem Dept, UNSW.”

    • In the absence of any further information I’d put it in the “plausible” category. It appears to use ionic liquids – I know what these are but have never seen them used in a cleaning application before.

      But there is a contact name at UNSW so I’ll look into it further. It certainly looks very interesting.

  57. Hi there, I was hoping you could please suggest something to remove old dried sticky tape (not just the residue) stuck on a colorbond pergola. Thank you.

    • Get some hydrochloric acid from the hardware store. Follow safety instructions on label. Dilute 1 part in 3 (eg add 200mL acid to 400mL water) and tip onto marks. Leave them to soak for a few minutes and you’ll see them dissolve. Then just wash away with water. Repeat as necessary or increase concentration if required

  58. Hi, How do l remove hot wax stain from a mari high polished table ?
    It has left a pink coloured stain …… haven’t tried anything yet ,I’m frightened to make it worse…..I please help Dr Chemical..!!
    Thanks. Marianne

    • This one’s a bit above my pay grade I’m afraid. I would say that what has happened that the hot wax has stripped off the polish on top of the table and also stripped some of the natural oils out of the Marri. If it was my table, i’d find out what type of polish it was and just repolish it, in the hope that the natural oils would replenish the surface with time (which is reasonably likely). The alternative of course is restaining it, but I wouldn’t even know where to begin when it comes to matching woodstains. The paint desk at Bunnings may be able to help – they sometimes have people with quite a lot of knowledge in these areas. Or you might just have to contact a French Polisher

  59. dog urine stained a cream carpet (not wool). My daughter put soda water and bicarb soda on it and it dried hard. Next it was dampened and carpet cleaning powder applied. Stain still there and fibres stiff. What next, how to remove the stain?

    • First thing to do is remove the dried bicarb, and then next thing to do is remove the urine smell. Fortunately vinegar can do both. Tip some on until you see no more fizzing, then just blot dry. You ma need to rpt if you see and dried powder when it dries. When it’s all gone the vinegar will neutralize the urine smell by acidifying the amines. Then you could put some Vanish carpet powder on it to finish

  60. Hello, I spilt brasso on a unpainted brushwood ( paintable plastic textured to look like rough timber) garden storage box. I haven’t tried anything yet . what can you suggest to remove it? It’s been spilt a while now and looks like rust. Thanks

  61. Five years ago I had my wooden boards polished with a water based varnish. Over the last 6 months white marks are appearing on used and unused areas of the floor, I invited a floor polisher in to get some advice. I was told that the patches were separating from the floor, no known reason and that I would have to have the whole floor redone.

    I am in my 70’s, a pensioner and the furniture is immovable…other than paying thousands for a commercial mover to move it. Is it possible to fix these marks?

    You gave me the name of the Carpet man….he does not know anything regarding wooden floor problems….thank you for your valued time

    • If the floor polisher says that the patches are separating from the floor, then I’d be going back to the person that laid the varnish. This shouldn’t be happening after 5 years. If you get no joy there I’d be taking it up with ministry of fair trading (Dept Commerce). I’ve had some dealings with them in the past and found them helpful

  62. Last night I began stripping an old cedar chest with Citri-Strip QCG73801T Paint and Varnish Stripping Gel. Upon finishing up last night, I put everything I had used and/or had dirtied up (rags, scrapers, bottle of gel, etc.) in a plastic bag and brought it all inside including the cedar chest still with a residue of stripping gel on it. It says that it is safe for indoor use so I really didnt think anything of what I was doing. Now I’m at work this morning and I’m experiencing some minor difficulty with breathing. Also, I’m now worried about my dog being in the house experiencing some prolonged exposure to any harmful toxic chemicals. I will take everything back outside at lunch nevertheless, and my dog is in a kennel that is not in the same room as the cedar chest right now – but the house is small. Anyways, will he be okay being exposed to that for the next couple of hours?

    Thank you.

    • It’s not the Citristrip. The active ingredient is NMP which is completely safe (and odourless) – that’s why it’s used. The citrus smell is a natural extract from citric fruits (orange oil). It sounds like it may be some allergic reaction to something but I have no idea what it is.

  63. I so not have a comment I have a question…so please pass this on the Dr Chemical. Five years ago I had my boards polished with a water based polish. Over the last 6 months white marks are appearing on used and unused areas of the floor, I invited a floor polisher in to get some advice. I was told that the patches were separating from the floor, no known reason and that I would have to have the whole floor redone,

    I am in my 70’s, a pensioner and the furniture is immovable…other than paying thousands for a commercial mover to move it. Is it possible to fix these marks?

    Or would it be possible to purchase a normal home polishing machine and just put wax on the floor as it peels off? I can tell you I am beside myself and am in great need of assistance. Thank you for your valued time

    • That advice doesn’t sound right. I’d be getting a 2nd opinion if I were you. I’m not sure where you are, but if you are in Perth call Duncan Beatty at Clean Underfoot on 0418 916245. Alternatively Bunnings hire floor polishers, and they normally have people who can give good advice

  64. Hi Dr Chemical
    My dog urinates on my plants in the garden and is killing them of, is there anything i can do to resolve this problem, kind regards Geoff

    • Get some jars of Vicks Vaporub, take the lids off, and sit them near the plants. I’m told it works well, as the menthol fumes mask the marking odours that the dogs are looking for.

  65. i have a pure wool carpet. While taking out Christmas tree the water in bottom tipped out. i sprinkled bi carb over & cleaned with warm water, vinegar, detergent & it didnt work. I then called a carpet cleaner who used something that he said wasnt vinegar but smelt the same. Then steamed cleaned it. It looked as though the stain was gone. After awhile as the carpet dried the stain was back.
    can you help

  66. What a wonderful site! I have an indoor teak table oiled with a mix of linseed and turps which has gone sticky in high humidity. What do you suggest I use to strip it off that won’t damage the wood?
    Stuck!

    • Linseed oil oxidises in air and polymerises with time. If anything will work, it’s turps. Failing that try “Easy Cleanup” from Bunnings, or acetone

    • Buy some washing soda (not baking or bicarb) from the cleaning aisle in the supermarket, make it into a paste with water and a scourer and it will work a treat

  67. Usually when the guys working in the factory of the business that I work for come into the office area they leave their work boots at the door. One of them forgot to do that and has left oil footprints on what I think is synthetic carpet. What can we use to remove the footprints? It looks a bit like a crime scene at the moment.

    • It’s a bit tricky as leather is pretty fragile. Wet a rag with metho and soak it against the mould. Eventually it’ll kill the mould and it’ll be able to be brushed away but it might take a while

  68. I oversprayed a spring controlled moveable arm on a piece of equipment at work and now the arm won’t stay in place where I put it. Is there anything I can do to counter the overuse of spraying too much WD40 on the spring mechanism?

    • If that’s what it is, any acid will get it off. Have a look at the labels on your bathroom cleaning products. Get some Ajax Spray & Wipe Bathroom if you don’t have any

    • Bit tricky as I’m not sure what it is. Try Preen Oxy-Action prewash. Spray it on and leave it – it might take a while but it should do the job. You may have to do it a few times

  69. Hi
    Excellent show on Curtin, thankyou. Two questions. Firstly how to remove rust stains in the bottom of a swimming pool. Made by my daughters hair grips!
    Second question, how to remove engine oil stains from pavers.
    Mark

    • If you have emptied the pool you can get th rust off with hydrochloric acid (1 part in 3). wear gloves and safety glasses. To get oil stains off pavers sprinkle some caustic soda flakes on the area. Wet down with a minimum amount of water then use a stiff broom to scrub it in. Then hose off with a HP cleaner. But it won’t get it all off as pavers are porous

  70. Hi Mark, Can you please advise the best way to remove a black scuff mark from a white carpet. this carpet is new and never been shampooed!
    Cheers
    Anne

  71. Hi , what can I use on my fibreglass pool to remove the dullness of gunge build up above the waterline !! Have tried liquid Jif Cream cleaner but to no avail !! Would like it cleaned back to its original shiny surface if possible , your program on curtain fm is not worth missing as it is superb !!

    • I’d try oven cleaner on it – spray on, allow 30 sec or for it to react, then wipe off. If it’s organic buildup it’ll work, but if it’s inorganic it won’t. In that case try an acidic bathroom cleaner (such as Easy Off with sulphamic acid as the active ingredient)

  72. Dr Chemical
    How do I remove red dust stains from a vehicle of the type people get from driving in the north of the state. I assume it is the iron in the dust which is the problem.
    The worst surfaces are galvanised steel, aluminum and plastic body parts.

    Regards Steve

    • The red dust is due to either clay or iron. Where you can get to it squirt oven cleaner onto it – that will neutralise the acidity that the red dust has (if it contains iron) that causes rust, and will make it easy to wipe off

  73. Hi I have just about to open a cafe and am stocking up on cleaning chemicals. When I am looking at a degreaser for the floor it says it can’t be used on polished or sealed floors. What exactly does that mean as not very clear on the internet. Also a few of the stainless steel appliances have what looks like run marks on them, how has this happened and can I get rid of them.

    Thank you

    • The best polish for stainless steel is Brasso. With a bit of elbow grease it’ll get the run marks off. Best floor cleaner is ammonia. 1 part in 50 generally, or higher if the floor is dirtier or greasier

  74. Hi Dr Chemical,

    Is there anything I can use to clean dog urine from carpet? Also is there something I can use to deter my dog from doing it again?
    Kind Regards
    Christina

  75. Please could you help with the removal of oil stains on a cotton top and also the best way to clean grout in-between the tiles on a 14 year floor. Have tried a few tile and grout cleaners with limited success.
    Thanks a million
    Regards Josie

    • For oil stains use an oven cleaner. Spray it on, work in with your finger and rinse. Use AJAX Professional Bathroom cleaner for the grout

  76. Hi I have a chair that is covered in100 per cent polyester luxasuede,I was advised by the retailer to use there cleaner but it has left water marks, is there any thing that can be done to get rid of the marks.

    • That’s a tough one – water marks are very hard to get off suede. Someone asked a question on my blog a few weeks ago, and someone posted in with a solution, but I can’t remember what it was, but if you browse the questions you should find it

  77. hi dr chemical have been listening to you on Jennys show can you please tell me how ican get white coffee stains off concrete in the garage I have a disability daughter he smokes in garage and falls asleep and knocks her coffee all the time I need something as I have to hand this house over in a week hope you can help me thank you very much

  78. Could you please tell me how I can remove some of the glue that is used to join bamboo flooring that has splashed and dried on vinyl lino, also wooden cupboards.
    This happened over a year ago and I have tried every thing I can think of to clean the dried stuff off with no success.

    • Acetone will do it, but do a spot test first to see that it isn’t damaging the surfaces. If it is, try metho – soak a rag and sit it on the glue for an hour or so – that should shift it

  79. Hi how do I remove hard solid antiperspirant build up from business shirts. I’ve tried baking soda vinegar hydrogen peroxide but no combination seems to work. I need some thing that will dissolve the build up which I know is the aluminium in the antiperspirant. Please tell me something thT will finally work.

    • Baking soda and vinegar won’t clean anything, as you’ve no doubt discovered. I’d like to know what conc peroxide you used, as it is not an over-the-counter chemical. I’d try an acid first – get some Easy Off bathroom cleaner (forget the actual product name) with Sulfamic Acid (listed on the label). Squirt that on and see if it does anything. If that doesn’t work, try an enzyme cleaner – Biozet liquid laundry detergent. Rub in with your fingers – allow some time – enzymes have a slow mechanism of operation. Rinse and repeat. Failing that, try an oxidising prewash (Preen OxyAction). Spray it on then leave it. last resort, a premium brand whitening toothpaste (that contains peroxide). Rub it in, and rinse and rpt if necessary.

      • Hi just thought I would let you know the Sulfamic Acid worked a treat to remove even the worst hard residue from 16 shirts. I bought a $12 bottle of a Descaler from Bunnings which was 99 per cent Sulfamic Acid Mixed it with water as per instructions on container and soaked the armpit area of the shirts in this solution for several hours. I used all of the sulfamic acid as I would mix a new solution most days. Some of the shirts needed to be treated twice but the results were amazing. Thank you for your help.

  80. We have bought a house with “glass cancer” already etched in!! I have been using bicarb & white vinegar & after reading your article bought Bam Easy Off. Have used it twice & seems to be worse!!! What do I do now????

    • I’m afraid it’s too late. Glass of course doesn’t get cancer – it’s a term invented by Shannon Lush because she doesn’t understand the chemistry of glass. What has happened is that the alkaline soap scum will etch the glass over time. When you remove the soap scum, you see the valleys and ridges created by the etching process. Often this can look worse, as you have removed the soap scum that was filling them in. So it can look like there’s still stuff on there when there isn’t – essentially you’re looking at the photographic negative of the image created by the soap scum.

      The only solutions are to either mechanically polish away the etching without leaving scratches, but I don’t know enough about this to suggest how you could do it, r attempt to fill them in with a silicone polish. I’d try an automotive polish on it and see how it looks. It certainly won’t fix the problem but it will probably improve it

    • Use Biozet liquid detergent as a spot cleaner. Rub it in with your finger – that will ensure the right temperature for the enzymes to work at their optimum. It won’t happen quickly – enzymes take a few minutes to work their magic, but it will happen

  81. Hello again Dr Chemical,
    I posted a question about efflorescence on my house bricks. It stayed on your website for a couple of weeks unanswered but now it has been removed.
    I don’t understand why.
    It case that was an accident I’ll try again.
    We have a new (4 years old) house. On a couple of spots efflorescence has appeared on the bricks. This is seen as a white powdery looking stain.Nothing I have tried will remove it.

    • Very difficult to remove, as it is essentially insoluble salts. Try a bit of hydrochloric acid (1:1 in a garden sprayer) to remov any calcium carbonate. Other than that, try wetting it. What colour are the bricks? If the colour goes away while it’s wet, then all you have to do is create a permanent wet look. You will find some clear coat products at Bunnings that may help to produce this effect.

      • The bricks are a dark grey/brown colour. Yes, the white marks do seem to go away when the bricks are wet. I will try your ideas – the hydrochloric acid first, then if that does not work, a clear coat from Bunnings. The clear coat will need to be a matt finish I suppose or it would stand out from the rest of the bricks on the house.

        • Be a little careful with hydrochloric acid on dark coloured bricks. It can discolour them, although this process is reversible with high pressure cleaning. Yes, matt finish clear coats are available

  82. Hello Dr Chemical, We have a four year old house which we think looks really nice. However, there is one problem regarding the appearance. On several spots efflorescence has appeared on the bricks and nothing I have tried has removed it – acid solution, stiff brush, high pressure water spray etc.
    Do you have any suggestions?

  83. Camebak Poduim Chill cycle drinking bottle has a removable clear plastic like drinking nipple. I rinse with hot soapy water after each ride but black spots eventually appear which are virtually impossible to remove; have tried soaking in a mild bleach solution – nipple goes pinkish & spots stay; scrubbed really hard with Jiff but has no effect; tried boiling but spots stay, nipple goes soft but recovers. I have emailed the manufacturer but ‘no response’. It appears that ‘some’ other riders have the same problem but others do not – any ideas?

  84. Hello,
    I have recently made liquid Castile soap and wanted to thicken it up for dishwasher liquid purposes. I have read that using table salt will help to thicken it. I did try this, the results not very useful. It was either too thick/clumpy or too liquid, there was no happy medium with adding the salt a teaspoon at a time. Do you have better suggestion to thicken the soap?

    • Nope – it can be done but you’d need an ultrasonic emulsifier and a zeolite=based thickening agent, neither of which I’m guessing you have lying around

  85. Hello I am about to paint my childrens outdoor timber cubby house and wanted to know what could I add to the water based paint to deter/prevent mould besides the additives you can buy?

    • Sugar soap is an alkaline cleaner. It’s a little difficult to see how it could damage the floor. But any residual sugar soap will be removed by an acid (such as vinegar)

  86. At work I over filled my forklift battery and my boss is mad cause it left black sticky stuff and white marks and tracks where u drove over it I put baking sofa on it it absorbed some of it now just white is there anything that will take it off the floor

  87. How do I remove mold from the outside of my Jeep without damaging or removing the paint? Is there a Canadian product you’d know if that would help keep it off for good? I continue to wash it but washing only removes the mold and not the spores, which are the reason the mold keeps coming back

    • Oven cleaner will get it off. Can’t offer any suggestion as to stop it coming back other than to keep a silicone coating (with polish) on your paint

  88. Hi Dr Chemical

    I’m a school teacher and want to clean those grubby plastic school chairs. Want them to look as clean as the day they were bought without using a lot of elbow grease. Can you please tell me what to use? Thank you!!

    Miss N

  89. Hi dr Chemical, i am about embark on the xmas cleaning around the house, i need to remove bore stains from my concrete path and i need to clean my driveway which is laid with paving bricks any ideas. I have a high pressure cleaner to help.
    Thanks John

  90. Hi Dr Chemical. I’m wondering if you can tell me how to remove a light blue film/stain from our white porcelain toilet bowl? It is below the water line, sort of around the bend. I usually clean the loos with bicarb and cider vinegar, so it’s not from using a commercial product. Crossing my fingers, and thanks. Susan

    • Well, part of the problem is your use of bicarb and vinegar – that combination of chemicals won’t clean anything (mainly because they neutralise each other). Try washing (or caustic) soda (or drain cleaner – the mechanism is the same). Tip it in, let it sit for at least half an hour, then flush. If you are going to use washing soda (available from the supermarket) you could add an acid before you flush – the violent effervescence may help dislodge the colour. Any acid will do (including vinegar) but I’d suggest some dry acid (sodium hydrogen sulfate) available from the pool section in Bunnings. You can also get the washing soda (sodium carbonate)from bunnings but it’ll cost you more than at Coles

    • Nothing you can do I’m afraid – the acid will already have reacted with the stone. Only chance is (very) high pressure water(>3000psi)

  91. Hi Dr Chemical
    I had my carpets cleaned a few months ago and the adjoining kitchen tiles have like a shadow type mark on them now. How could I get rid of this?

  92. Hi Dr Chemical,
    The water level of the S trap in my bathroom floor waste is a few mm above the incoming drain pipes from the vanity, bathtub and the shower recess (the drain system is on the second floor and rather than increase the thickness on the concrete slab, the plumbers and builder, cramped the drain pipes within the thickness of the slab. The house was built 12years ago). Therefore when soapy water comes from one of those drain, the soap scum etc flows into the other two drains and after drying between usages the soap and debris builds up. Their’s always a smell, we have cleaned it with practically everything but after a day or two the smell returns.
    It’s very hard to physically clean the drain.
    Could you please suggest a cleaning product that we could use that is easy to use and gives us a clean smelling bathroom for a few weeks.
    Thank you for your time and knowledge.
    Pri

    • I need some more details – what exactly is the smell? If it’s soap scum, however I’d try acidifying it. Either use vinegar or “dry acid” available from the pool chemical section of bunnings. Also I’d be complaining to the builder, and if they won’t help go to consumer affairs – by your description it most certainly does not comply with the relevant standards

  93. My sofa’s cup holders are black plastic, The rim is painted silver. Some of the silver has rubbed off. How can I safely remove the rest of the silver from the cup holders?

    • Very difficult to say without knowing what the silver actually is. You could try acetone, but be careful- it may damage the plastic. Try rubbing a bit of acetone on an inconspicuous part first to see if it damages the plastic. Or squirt some oven cleaner onto a paper towel and rub – that might work too

  94. Hi Dr Chemical. I recently cleaned some tiles with a liquid caustic solution and splashed the aluminium window frame while doing it. This has now left nasty white marks along the frame. It feels like it has etched the frame so to speak. Can you suggest a remedy please??

  95. Hi
    How do I get sunscreen marks off a gren colourbond roof -unfortunately done by adelaide hills very average builders?
    thanks
    Phil

  96. We have a wheelchair taxi that has had it floor tag by a passenger. The flooring is thick chip board but has a rough vinyl coating – they have used a black marker pen – is there anything that can be used to remove it

  97. Hi – my problem is not stain removal but maybe you might have a solution – keeping my fingers crossed. I get a wet dog smell in my sink/dishwasher and on my dishes at different times – there seems to be no rhyme or reason – no particular event or time. I get it on my dishes when I wash them in the sink or in the dishwasher. I have looked on the internet and it seems to be a common problem. I have asked different plumbers and they have no idea. It is so strong at times that it makes me feel sick. My hot water heater is only a few years old and I clean the dishwasher filter regularly. I get it even when I dont have egg on the dishes as some have hinted that could be the problem. Its really frustrating – hoping you can help.

    • Hmm. What brand dishwasher powder do you use? Finish is the best. Also use Morning Fresh dishwashing detergent if you aren’t already doing so. Get back to me if they don’t fix the issue

  98. Hi, could you tell me if rubbing alcohol is the best thing to use to clean a light coloured leather lounge. Also, when you say ‘oil’ the leather after cleaning, what kind of oil do you suggest. Looking forward to your answer. Cheers Susi

    • Yep – it’s a very versatile roduct and won’t damage anything. Alternatively go to an electronics store and buy some isopropyl alcohol – it’s the same stuff but is 100% (rubbing alcohol is only 60%)

  99. hey, i was just wondering what the Ka value for phosphoric acid is (for an assignment) and if it is a strong or weak acid and how you can tell using the Ka value

  100. HI There

    We had a limestone fence built with an integrated mailbox. The front of the actual mailbox is stainless steel (I think) and the limestone has leached white marks onto the steel and I cannot remove it. I have tried CLR, vinegar, steel wool. Can you please help me?

  101. Hi Dr Chemical
    Once again, thank you for your fabulous site.
    My son is always looking for do at home chemistry experiments of sufficient complexity to submit for school assignments (Y10). Do you have any suggestions or know of any good sites that may have ideas.

    Thanks, Fiona.

  102. Please could you tell me the ingredients needed to produce refill inks for dry erase markers and their composition? Thank you.

    • You mean you get emails sent from the site? Go into Actions on your email menu and select “move to junk” – it will then give you an option for moving all emails from the site when they arrive

  103. I have removed old window tint from a lounge window, it was quite brittle and the top layer came off but has now left a cloudy look on the window. I have tried eucalyptus oil, method and hot soapy water but still not coming off. I have used a razor blade for a small bit but at this rate it will take for ever. Any Suggestions?

  104. I have sprayed an outdoor setting with high gloss white Dulux Metal Shield Epoxy Enamel on a windy day and the part of brick pave not covered by newspaper has become a lighter shade. How do I remove this?

  105. Hi Dr, thanks for yr wealth of solutions – an interesting read.
    My Q is how to revive a faded ‘charcoal ‘ aluminium pool fence? It’s design is thin tubular uprights & would make it quite tedious (@ least 40mt in length) ?
    Thanks

  106. Dr chemical, I have stains in the pillow case ( on my husbands pillow ) the pillow case is maroon and has dark stain on it. He doesn’t use any hair products other Shan shampoo. Have tried laundry spray and soaker to no avail. Cheers Joy

  107. Hi Dr.Chemical
    My mom spill some cleaning chemical for cement on our glass tile and now the tile lost its shine, she try cleaning it but it didn’t work. We try everything to restore its shine but its no use. What can we do.

  108. Hi Professor Chemical,

    Could you please advise me of your email address or contact details and I would like to contact you regarding a project that you might want to do together.

    Kind regards,
    Reginald

  109. Good afternoon,I have a polished and sealed dark marble bathroom floor which when I have all the lights on shows water,soap marks.I have been told to cut it back, repolish and seal.Can you think of an easier way to remove these spots.Kind Regards Tony

  110. Dear Mark,

    Can you please advise me how to remove window tint glue from a fabric car seat. We stripped the tint off some windows and a small piece (approximately 3mm x 1mm) of the sticky glue got stuck on one of the seats. We tried white spirits but the glue is still stuck in the fibres.

    Kind regards,

    Claude Tasmer

    • Hi Dr Chemical. How can I effectively clean the inside of my car windows? I have used Windex, Metho, Washing liquid, Bleach, Glen20 and just about everything known to man but I am always left with a foggy smeary window. I am a driving instructor and it is driving me crazy as I need a clear view when driving.
      Desperate

  111. Hi there – I am unable to find soda ash in any supermarket except the stuff used to balance the pH in pools and spas – is this the same product? This is for cleaning grout on the floor tiles.
    I have also found a product called ‘Grout King’ – it contains 350g/l phosphoric acid – works like a treat but I am wondering how much damage its causing?
    Cheers
    Jac

    • Yes that’s the right stuff. But you get it from supermarkets at ankle height in the cleaning aisle – it’s a bit hard to find. Where did you find the Grout King – I can’t find any info about it anywhere

      • Hi Dr Chemical,
        I have a tiny courtyard and I cannot seem to remove the stains left by my dog on limestone pavers. I have tried a range of natural and pavement cleaning products to no avail. Now I wash it down immediately, but I am trying to remove the old stains. Some set like concrete and even chipping bat it hasn’t worked. What do you suggest?
        Cheers
        Caroline

        • Yep, hydrochloric acid. Put it in a plastic watering can 1 part in 3 and pour it on. It will fizz and foam. get a broad broom and brush it over the entire area so yuou finish up with a uniform colour and then just hose off

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