When any impurity is burnt, its smoke becomes pure. If it becomes hard and something is made out of it, then it will also be pure. As has been said of sal ammoniac, that it is made out of impure smoke.
Sand and dust that is on of some impurity is pure on condition that the dampness of the impurity does not make them damp as well.
Gases that rise from impurities are pure. Worms that emerge from fruits are pure, but it is not proper to eat them if they are alive (or even dead). The same rule applies to the worms of wild figs, etc.
When edibles such as meat, sweetmeats, etc. get stale and begin to stink, they do not become impure. But when taking into consideration the harm that can be caused, it will not be proper to consume them.
The saliva which comes out from a person’s mouth while he is sleeping is pure.
An egg whose colour has changed is pure as long as it is not broken.
The skin of a snake is pure.
The water with which a dead person is given a bath is impure.
The skin of a snake is impure, i.e. the skin which is still attached to its body. The skin which it sheds is pure.
The saliva of a dead person is impure.
If one or two pieces of dung or excreta of a cow or goat fall into the milk while they are being milked, it is excusable as long as the dung or excreta is removed immediately. If it falls at some time other than the time of milking, the milk will become impure.
If a four to five year old boy who does not understand what wudhu is, makes wudhu; or an insane person makes wudhu, then the water will not be considered to be musta’mal (in other words that water can be used for wudhu by someone else).