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
Have tried all sorts with Gumption being the best up to date but still some glass cancer visible. A relative’s shower was so bad he was considering replacing the glass. I suggested trying a safety blade to scrape off the worst and he was prepared to take the risk with scratches. It can be done on a dry screen or a wet screen with pros and cons for each approach. 95% removed by scraping, the other 5% with Gumption. Perfectly clean screen, no glass cancer and no scratches. Tried it on my own and same result, glass cancer gone.
Hot water won’t damage glass, although I suppose that with enough exposure there could be some mechanical scouring occurring
I’m a Gumption girl myself!
I am a house cleaner and I have another theory I would like your opinion on. I usually see this effect on the area closest to the shower head and when the water is really hot. My theory then was that it was caused from really hot water hitting the glass or whatever the glass is treated with. I would have thought if it was caused by a cleaner or soap scum it would be more patchy. Thank you
Automotive car polishes like that typically are about $12 from an auto accessories store
Hi just wondering how much your paste is
Good idea. It adds a silicone coating like Mr Sheen, but it’ll be a thicker coating so it won’t need to be reapplied as often
Once you have your screen clean Polish it with a cream car polish. I use nu finish.
You will find once you have finished showering the glass has steam on it. Steam has no impurities in it so no spots. Do not be tempted to spray the screen with hot water to remove the steam as you are adding more impurities . Just finish and walk away I think you will be pleased with the results with the car polish.
I saw that product in Coles last week – right next to the Brasso. But it’s not “cancer” – it’s etched glass, and yes, the right level of mechanical abrasiveness could certainly remove it
If you google glass cancer there are several utube videos up that show how to remove it.
I just purchased “Bar Keepers Friend” from “Kichen Warehouse” online.
Well it works!! The dry pastier the better.
It doesn’t come straight off & the first application only gets a very minimal amount off which looks like it doesn’t work. I just did a small 10cm square & repeated the process about 4 times. Def has removed most of it & there’s no etching lines in most areas of that patch even when viewed from above so you can see down the glass. Not going to lie & say it’s easy as it is a slow process to get the layers of the build up from the hard water off.
But I’ll be persisting as it bugs me. It’s only happened in my boys shower as they got slack, in the other showers we squigee all the time after a shower & they are regularly cleaned.
Def worth buying as it’s not expensive & it would have multiple uses around the house. I’m very particular with cleaning & this does get it off.