Toilet stain removal

[Lobster]

I've just retaken possession of a house which I let out, and now need to prepare it for new tenants.

There is a very large, odd and unslightly stain over most of the bottom (only) of the toilet bowl, black - grey in colour. Haven't a clue what it might be and wonder what the panel would recommend hitting it with first? Acid? Alkali?

It's a very soft water area (my own loos, nearby, have no problems at all). Toilet and all pipework in the property was renewed 18 months ago, and there are no water tanks (all direct mains fed).

Thanks David

[The Natural Philosopher]

Try both. Alkali first..that will generally bleach out the colour - and then acid to etch any oxidates..

There isn;t much other than teh glaing and teh plastic pi[es that will stand up to serial attacks by strong acid and alkali.

[Lobster]

Thanks, just been round and tried the bleach actually - for no other reason than that's what I had in the cupboard.

Stain is more brown - grey actually. Also, it has well defined edges, as if it's broken away from the glaze there. Probably indicates that draining the bowl and trying mechanical abrasion would see it away, but hopefully I won't have to go there!

David

[Andrew Gabriel]

Given it's a soft water area, I would try a cleaner which is good at organic dirt. Pre-heat the utrap water by pouring hot water down the loo (don't thermally shock it too much in one go or the pan might crack). Then use a good dose of either washing machine detergent or dishwasher detergent dissolved in hot water, pour in, and leave some hours (overnight, next day) before takling with the toilet brush. If it is an organic residue, it should then come off very easily. Similar treatment with soda or caustic soda might be worth a go if this fails (don't use hot water with caustic soda, and read warnings on the packet carefully first).

Note that when trying different cleaners, flush the previous one well away first, as there are many combinations which when mixed will give off toxic gas.

[meow2222]

I've done this very effectively with HCl, aka brick/patio cleaner. I put some in and left it half an hour, and a lot came away. Left some more in there and when I came back there was nothing left, all eaten. HCl is good for organic material.

NT

[Guy King]

The message from [e-mail] (Andrew Gabriel) contains these words:

I once saw an emergency trachaeotomy done on a French schoolgirl after someone mixed cleaners in a loo in Hyde Park.

[Stuart Noble]

Cement?

[Andy Dingley]

Also very bad for glazed ceramics. If there's invisible surface damage already you may find this becoming visible as dark crazing.

Use conc. H2SO4, which is (surprisingly enough) what's sold for just this purpose.

[gort]

It be that the surface glase has been worn/broken away and what you are seeing is the base material of the bowl?. Especially as you say it has defined edges.

Dave

[meow2222]

its normal bog soilage

NT

[meow2222]

Does this come from plumbers merchants only, Ive not seen it in screwfix/toolstation etc. I've got H2SO4 but not in conc.

NT

[Andy Dingley]

Mine just comes from the local hardware shop - 96% and made by "Thaumaturgy Ltd", which has to be the best chemical company name of the last century. It's the cheapest source of H2SO4 for electroplating.

I don't use it as toilet cleaner. Haven't needed that sort of scumpower since I was last involved with housing associations (and right at the bottom end of things). For my own I just use sulphamic, which I find to be cheapest from Sainsburys own brand conc acid toilet.

[Andrew Gabriel]

;-)

Another cheap source is a tub of Furnox DS-3 central heating descaler, which is sulphamic acid (plus a PH indicator to show when it's used up and a scent so you don't accidentally drink it and can tell when it's all flushed out).

[Lobster]

OP reporting back for the sake of completion....

Bleach, which I tried first, did absolutely sweet FA; followed that up with an own-brand acidic limescale remover from Sainsburys, which worked like a dream.

God knows what these people were eating...!

Thanks for the advice David

[Helen Deborah Vecht]

"Lobster" typed

Cured for 69p![1]

Lots of calcium, methinks; maybe much dairy produce. Perhaps they were not in the habit of flushing the loo after nocturnal visits (or ever!?); this can leave loads of gunk due to urine being concentrated.

[1] Cost on my latest Sainsbury's receipt.

[The Natural Philosopher]

Just check the underside front of any loo seat in an all female household.

Encrustation isn't in it.

[Mary Fisher]

...

It's not always eating habits. We've have a dark rim at the water line since we began taking certain (prescribed) drugs. It cleans off easily but it was noticeable from the third or fourth day.

Mary