Practically in any teapot the grayish raid – scum which is very difficult washed by normal cleaning agents is formed over time. How to get rid of it? You can clean scum from teapot in several ways. All of them are very ordinary and will not demand from you great efforts.
1. Pour water in teapot and add one or two bags of citric acid (it can be got in grocery stores). Boil the turned-out solution and let's teapot stand a little (10-15 minutes). After that drain water and properly rinse teapot. After that it will be necessary only to get rid of residues of citric acid – once again to fill teapot with water, to boil it and to pour out. Instead of citric acid it is possible to use vinegar – but keep in mind, it has much more persistent and strong smell.
2. If the layer of scale too thick, and from the first was not succeeded to clean off it, then use other method. Fill teapot with water, pour tablespoon of soda there and you boil water of 20-30 minutes. Then rinse teapot and repeat operation with citric acid or vinegar – but do not switch off teapot right after boiling, and give to solution of boil acid (same 20-30 minutes). After that the scum will become friable, and it can be wiped without effort scouring sponge.
3. Besides, it is possible to get rid of scum in the "national" way: as weak solution of acid instead of water with vinegar and citric acid you can use carbonated drinks (such as "Sprite" or "Coca-Cola", or any other sparkling water which part citric acid is). However, before filling in "pop" in teapot, it is necessary to get rid whenever possible of gas (to allow to stand in open form, stirring slowly with straw). Also you should not pour them more than on half of volume of teapot.