Shannon Lush Gets it Wrong #1

A substantial amount of what Shannon Lush says about the chemistry of cleaning is wrong. This shouldn’t surprise us, as she is not a chemist.

Paramount among these is the oft-given advice of mixing bicarb with vinegar. I have heard her say on air that this “makes hydrogen peroxide” and that’s what does the cleaning.

This is quite incorrect, and I and several of my colleagues have sent her emails in this regard down through the years. She apparently now realises this, as on Tony Delroy’s show on nightlife this evening she said that it “forces oxygen into things”

I was unable to get an explanation of this, however. For her benefit, when you mix bicarb soda and vinegar together, the reaction products are sodium acetate, water and carbon dioxide, not oxygen, and none of these compounds have any cleaning properties whatever.

The balanced equation is:

NaHCO3 + CH3COOH = NaCH3COO + H2O + CO2

But let it never said I wasn’t open-minded. I now invite Shannon Lush to answer this question, and I’ll print her answer in full on this site.

Other things that she said that were wrong (off the top of my head) were

1. You cannot remove silicone (from Mr Sheen) from a plasma TV. I’m not sure why you’d want to remove Mr Sheen, as it is a terrific general purpose cleaner, but it can be removed with Shellite (from a hardware store) – that’s what painters use to pretreat automotive surfaces that have often been polished with silicone polishes.

2. You cannot use an acidic cleaner to clean marble. In fact marble is incredibly chemically resilient, which is why we still have marble structures going back to Roman times, and you can use hydrochloric acid on it if you want. But if the problem was mould and mildew, you’d use caustic soda on it.

3. You can mostly replace your laundry powder with bicarb soda. This advice displays an utter ignorance of both the chemistry of bicarb soda and washing powders. Washing powders are highly sophisticated formulas that contain up to 9 or 10 different components (surfactants, enzymes, oxidizers, builders, alkaline salts, fluorescing agents, antiredeposition agents, free-flow agents, fragrance, softeners), and you simply cannot replace these with any one chemical – particularly bicarb soda, which has almost no cleaning properties whatever.

8 thoughts on “Shannon Lush Gets it Wrong #1

  1. Hi

    Shannon oftens mentions the use of Oil of Gloves to “kill” bacteria – not to simply whiten the wall etc. Is this the case?

    • Yes – apparently it does. I haven’t looked into it in fine detail, but when I made an enquiry of one of the places that sells oil of cloves they sent me some refereed publications, but I haven’t had a chance to read them yet. But prima facie – yes it works

  2. Hi Mark,

    I’ve seen a couple of people on a FB page recently advocating using mixtures of either vinegar or citric acid and bicarb to clean things. I pointed out that they would be neutalising whichever acid they were using, making sodium acetate (in the case of the vinegar) or sodium citrate (in the case of citric acid), carbon dioxide, and water (and that that was what the fizzing they reported was). I suggested that either component would be more effective alone than combined.

    One woman has reponded that the reaction produced carbonic acid (which from memory is just carbon dioxide in water, so that bit sounds plausible), and was claiming that the carbonic acid was “what gave these mixtures their cleaning power”.

    What’s the “dirt” on the relative effectiveness of vinegar, citric acid and carbonic acid for household cleaning? (One post was just talking general surfaces, and the other was specifically about cleaning toilets.)

    Thanks! :-)

    • Unfortunately the comment about carbonic acid demonstrates a lack of misunderstanding about acid base chemistry. Carbonic acid exists with CO2 in a pH dependent equilibrium: H2O + CO2 = H2CO3
      The pH needs to be below about 3.6 for there to be significant levels of carbonic acid, and a mixture of bicarb/vinegar would be well above this. But it doesn’t have any cleaning properties anyway, so it’s a moot point.
      Of the three acids you mention Citric is the best for cleaning bathrooms, and in fact is the active ingredient in Shower Power. Vinegar is next best and carbonic the weakest. The only reason people use vinegar/bicarb is because it fizzes, and people associate foizzing with cleaning.

  3. Hi, what is the best way to remove mould from my bathroom ceiling. At the moment it is not too bad or widespread but I want to nip it in the bud. Will a mix of vinegar, distilled water, bi- carb, and oil of cloves ( as recommended by a popular lifestyle programme) do the trick?

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