Last Monday on 6PR a caller on 6PR asked Shannon Lush how to clean shower screens.
She advised against using commercial products and instead suggested vinegar.
Let’s have a look at it. Exactly what is the grime on shower screens?
There are essentially two components of shower scum – mineral deposits (usually calcium carbonate) and soap scum. Soap scum is either the calcium or magnesium salt of the soap molecule.
Either way, the deposits are alkaline.
So to get them off, you need an acid. It needs to be a strong enough acid to dissolve the alkaline salts, but not so strong that it’ll either etch the glass or attack the alloy trim in the shower.
As it happens, there is only one acid strong enough to etch glass – hydrofluoric acid – and it’s certainly not sold over the counter to the general public. Other strong acids – hydrochloric and sulphuric acids – are available over the counter, but they would attack the metal in the shower recess so we won’t use those.
Vinegar – or acetic acid – is not a bad option, but a better option is sulphamic acid (found in BAM and also a toilet cleaner that Bunnings sell). It’s a stronger acid, will get the alkaline salts off easier, but won’t damage the metalwork.
But whatever you use, you may find that it never comes quite clean, and appears to still have deposits on there.
This is caused by the soap scum etching the glass. Soap is make from caustic soda and fat, and so the salts of the soap are highly alkaline. And glass is much more prone to etching by caustic soda than any acid. Anyone that works in a lab knows that you don’t store solutions of caustic soda in glass.
So the highly caustic soap scum will etch the glass. So even after you clean it off, you can still see the etching behind that it has left. I suspect this is what Shannon Lush calls “glass cancer“: But unfortunately her advice to use Goanna Oil won’t make a scrap of difference
So the lesson is – don’t let highly caustic soap scum build up on your shower screen – keep it clean
Dear Dr Chemical – spot on!
Have just used stainless steel wool and BAM…it works!
I will probably need to use some wet and dry as suggested above to get the final small bits off, but it works!
Is it worth having these beautiful clear glass showerscreens at all?
A return to the frosted bumpy surfaces of the 1950’s would solve all these shower worries !!
In that case, try some wet and dry abrasive paper
I’ve tried steel wool doesn’t remove “glass cancer”
All the information I have is that was a razor blade. If you scroll through the questions in this section you’ll find it eventually.
hey there,
what kind of scraper did you use for the glass and where can I find one??
Try Ajax Spray & Wipe Bathroom (with lactic acid)
i’ve got shower screen scum and i’ve tried a lot of products, but i’ve never heard of glycerol,an at the moment i’m trying ceropal,i’v had these scum stains for many years,it’s only now i’m more determent than ever to get rid of it. what’s amazed me is that from day one we always hose of the soap from the glass screen after avery shower,so it has to be water scum as well.i’m open to suggestions.
Please don’t malign renters – not all of us are pigs (and I know many grotty owners)!
Well done. But it’s not cancer. It’s a chemical compound of some sort. But you’ve answered a question for me – I thought it was etching, but if it can be scraped off it clearly isn’t. Steel wool may also be worth a shot. Contrary to popular belief it won’t scratch glass