Is Shoe Polish Safe?

Huh? shoe polish?

How could something as common as shoe polish not be safe?

Well, unfortunately some shoe polish has a chemical in it that just shouldn’t be there, and it’s all our fault!!

You see, the chemicals that are in consumer products are not necessarily the best chemicals for the job – they are the chemicals that Joe Public thinks are the best chemicals for the job. That is, we are sold what we think we want, rather than what we need, and the single best example of this that I know is shoe polish.

Shoe polish – the older type formulas – are a mixture of oils and waxes that we rub with a stiff brush, allow to dry, and then buff to a shine.

When these were developed years ago, the best solvent to dissolve all the oils and waxes with a chemical called nitrobenzene. It was known, even at the time, that it was a chronic toxin – but it wasn’t acutely toxic, so it was used.

I should explain the difference between an “acute” toxin and a “chronic” toxin.

An acute toxin is one that would have a very quick effect upon you if exposed even for a short time. Any chemical in this category will have a warning diamond on it that looks like this:

Generally, chemicals in this category would not be available to the general public anyway, but it’s good to be aware of it nonetheless.

Chronic toxins are far more insidious. It refers to a toxic effect that is the result of exposure to the chemical over a long period of time. By nature, this kind of effect is very difficult to quantify, as it is difficult to isolate a particular toxic effect to a particular chemical if it has occurred over a long period of time.

Therefore, we should be very cautious if there is even the suggestion of a chronically toxic effect. Nitrobenzene falls into this category.

If you scroll down to section 3 of the MSDS you will see that it says:

Potential Chronic Health Effects:
Extremely hazardous in case of ingestion. Very hazardous in case of skin contact (irritant), of eye contact (irritant), of inhalation. Hazardous in case of skin contact (permeator). CARCINOGENIC EFFECTS: Not available. MUTAGENIC EFFECTS: Not available. TERATOGENIC EFFECTS: Not available. DEVELOPMENTAL TOXICITY: Not available. The substance is toxic to blood, kidneys, lungs, liver, mucous membranes.

Now here’s the thing. Several years later, they were able to develop a formula that worked just as well as the nitrobenzene, with a different solvent, that was not toxic.

But it smelled different, in fact it was odourless. And that’s what caused the problem. You see when people pick it up and start using it, they said “this isn’t a real shoe polish – it doesn’t smell right”

You know the smell I’m talking about – if you use the old-style traditional shoe polishes, they have a characteristic smell which you instantly recognise. That smell is  nitrobenzene, and when it was removed from the product, people simply stopped using it, because it didn’t “smell ” like shoe polish any more.

So it has persisted to this day.

So how dangerous is the Nitrobenzene, and what precautions should be exercised when using it?

Like any chronic toxin, the mechanism of its effect is not well understood, simply because the chemistry of the human body is so incredibly complex.

So the best approach when using it is simply to be careful, and this involves two things:

1. Always wear gloves when using it.

2. Always use it outside (or in a well-ventilated area) where you will not breathe the vapours.

If you adopt both of these straightforward procedures, it’s perfectly safe.

On the other hand, many shoe polishes these days are water-based – they’re the ones where you paint the polish on and it’s shiny immediately. Although they work, in my opinion they aren’t as good for the leather in your shoes because they contain water.

Stay tuned for a post, coming up soon, on how to look after leather.

In the meantime, let’s hope that the older style shoe polishes are reformulated with a less toxic solvent, but I won’t be holding my breath.


The Most Potent Flyspray Ever!!

I miss the good old days.

You know, back when Dirty Harry called criminals “creeps” instead of “suspects”, when skim milk had never been thought of, when you could buy hamburgers with beetroot, and when you could walk into a supermarket and buy a can of  Pea Beu Tri-Kill

This stuff was quite simply the most potent fly spray ever to hit the Australian market. It was a direct competitor to the Mortein Fast Knockdown (in the red can). Although it never outperformed Mortein in terms of sales, it certainly outperformed Mortein in terms of its insect killing ability.

The reason for this was not just its insecticides.

Firstly, it was solvent-based, like the Mortein, but unlike every fly spray today (except for the Mortein FK) which are water based. Being solvent based the Tri-Kill vaporised into smaller droplets as it was sprayed into the air (flash vapourisation), resulting in many many smaller droplets of insecticide than you’d get with a modern spray. Also the tinier droplets go further as they aren’t as heavy.

Secondly, the Tri-Kill had a spray rate that not even Mortein could match. Whereas Mortein had a spray rate of about 2.8 g per second, and no fly spray before or since has ever delivered more than 3 g per second, the Tri Kill produced a whacking 3.6 g per second !!

It’s the kind of fly spray dirty Harry would use. You pressed the button and ka – wooshka!! When you pressed the button you could actually feel a recoil!

It achieved such a high spray rate by using propane as its propellant.

Yes, that’s right – its propellant was pure propane!!

I can just see the marketing meeting now..

“here you go, here’s what’s going to knock Mortein off its perch”
“Tri-Kill huh? What’s it like?”
“Have a squirt…”
“Yeow!! It almost took my hand off!!”
“Yeah – good stuff in’t it?”
“What’s in it?”
“Oh, you know – propane”
“Propane? Isn’t that a bit dangerous..?”
“Have another squirt..”
“Ah yeah – I see what you mean. Well, I guess propane isn’t that dangerous is it?”

Consequently, it would stop flies (and roaches and spiders) in their tracks, quicker than anything before and certainly much quicker than anything since.

Much to no one’s surprise, of course, it was a flamethrower, and there were several anecdotal stories of it causing housefires!

And so when Reckitt and Colman acquired the product from Ciba-Geigy in the mid-1980s, they pulled it off the market immediately due to safety considerations.

Those of us who were working in the industry at the time grabbed as many cans of it as we could, but of course they eventually ran out.

I sure miss it.

But I don’t think the flies do…

Are Mercury Amalgams Safe?

Today a caller questioned the safety of mercury amalgam fillings.

It’s not a bad question. Since the Minamata Bay Disaster people have been concerned about the presence of mercury in the environment, and therefore, obviously, our mouths!

So how toxic is mercury anyway? Well, it depends what form of mercury you’re referring to. Mercury, like any metal, is inorganic in nature. Our bodies are organic, however, and for any metal to be taken into our bloodstream, it must be converted to its organic form.

Take iron for example. We all need iron – we know that – just ask Popeye (interestingly, the original idea behind the “I’m strong to the finish cause I eats me spinach” was about the Vitamin A in spinach, not the iron, but don’t tell anyone).

So we eat iron-fortified breakfast cereals such as Special K or Guardian because we know it’s good for us.  And what’s the traditional drink that we have with our breakfast? Why, OJ of course.

And here’s why – OJ contains citrates and ascorbates that bind to the iron, convert it to its organic form, and help it cross the lipid bilayer (the barrier to anything inorganic) and get into your bloodstream. In other words, it is now “bioavailable”.

So sometimes we want the metal converted to its organic form.

But for mercury we sure don’t. Luckily, mercury does not bind to any of the common things in our body like citrates or ascorbates, and any inorganic mercury that found its way into your stomach would generally pass right through you.

In fact there is no obvious source in your body for the conversion of the inorganic mercury to the metallic mercury. But we need to be careful – given the extreme toxicity of organomercury compounds, we don’t need much of a source – even tiny amounts can be deadly.

The Chemistry of Doorknobs

People in the past weren’t dumb. At least not all of them.

We often think they were, which is why we are always changing things and modernising things.

But sometimes our attempts at modernising are actually a backward step, and we come to realize that in years gone by people really did know what they were doing.

Take doorknobs for example.

Any old house will contain brass doorknobs, but we have now replaced them with much more flash looking polished stainless steel or any number of coloured plastics.

We understand that in the past people used brass because it was simple and cheap, looked good, and didn’t tarnish. In our cleverness we’ve now replaced it with things that are cheaper, look better, and don’t corrode or tarnish.

But is that all there is to doorknobs?

Well, aside from allowing us to close and open doors, doorknobs have another, very unwelcome, role in our lives – the transmission of disease. If someone has sneezed onto their hands, and they touch a doorknob, the germs and bacteria are quite happy to sit there until some other unsuspecting soul uses the same knob.

And here’s where brass has it all over any other doorknob material. Brass of course contains copper, which has natural antimicrobial activities and is the active component in many garden fungicides and biocides. Consequently, any germs that find their way onto a brass doorknob don’t last long – it is deadly to most of the common disease–causing germs and bugs. To achieve the same thing with other doorknobs you’d have to spray your doorknobs – every time they were used – with a disinfectant.

So next time you’re shopping for doorknobs and you see those gold-yellow items twinkling innocently amongst the much more flash-looking polished stainless and plastic knobs, just remember, there’s more to doorknobs than meets the eye.

Or next time John Cleese asks “All right, but apart from the sanitation, medicine, education, wine, public order, irrigation, roads, the fresh water system and public health, what have the Romans ever done for us?” we can now answer “they gave us brass door knobs.”