In message , stuart noble
writes

Christian McArdle wrote in message
...
Good idea. I've used the same principle on the rim of WCs. 10% citric
acid
solution is much stronger than vinegar and just as easy to handle.

I use brick acid. A bit stronger still...
And dangerous to handle..... and a bloody nuisance to store. Sulphamic is
the best of both worlds, but you can't just nip round the chemist's to buy
it.

I've got a 20 kg tub of it somewhere ....

right next to the caustic soda

--
geoff