Lime Scale Removal

IME the easiest way to do the rim is block the thing up with plastic bags or whatever and leave overnight. Any acid will do. About 200 gms of citric (£1.50 in the chemist) did it for me last time and no worries about it spilling on the floor, which it is bound to do if you fill right to the top.

I think most elizabethan houses have one now :-)

Not a good idea - It will convert the top layer of the scale into Calcium Sulphate which does not dissolve in water. The acid will not then do anthing to the rest of the scale. Stick with brick acid (hydrochloric acid) as calcium Chloride does dissolve in water. Take the advice from another post - do not add bleach until you have thoroughly flushed the system. Bleach and any acid (including Harpi) generate chlorine gas which is very unpleasant and was used as a poison gas in WW1

Malcolm

Or leave it to the qualified & experienced chemists who make things like Harpic.

AFAIK wallpaper paste falls apart in an acid environment

s/chemists/over paid marketing executives

Formulated limescale remover does seem to be the most unnecessary product. Personally, I just buy a bottle of "value" vinegar for 20p, it's good enough for most purposes though probably isn't strong enough for the OP's problem

tim

Absolutely. IME scale is soluble in any acid, but people leave it to build up for months and then want to remove it in five minutes.

Robert Dyas sell it for about £3 for 500ml. It works very well.