Najâsat (impurity) is of two kinds: one that is very thick or hard, and even if a little touches a person, it will have to be washed. This najâsat is called najâsat-e-ghalîzah (heavy impurity). The other is a little less and lighter, and is called najâsat-e-khafîfah (lighter impurity).

The following substances are regarded as najâsat-e-ghalîzah:

blood; stool, urine and semen of humans; intoxicating drinks; the excreta and urine of cats and dogs; the meat, hair, bones, and everything else of pigs; the dung of horses, donkeys, mules, cattle, oxen, buffaloes, etc; the droppings of goats and sheep; in other words the excreta of all animals; the droppings of fowls, ducks and wild ducks; and the urine of donkeys, mules and all harâm animals.

The stool and urine of a small child that is still being breast-fed is also najâsat-e-ghalîzah.

The excreta of harâm birds and the urine of halâl animals, such as goats, cows and buffaloes. The urine of horses is najâsat-e-khafîfah.

With the exception of fowls, ducks and wild ducks, the excreta of all other halâl birds such as pigeons, sparrows, etc. is pure. The urine and stool of bats is pure.

If a najâsat-e-ghalîzah that is thin and flowing falls on the body or clothes, it will be excused if the area on which it falls is equal to or less than a fifty cents coin in extent. If the person performs his salât without washing it off, his salât will be valid. But to refrain from washing it and to continue offering his salâts in this way is makruh. If it is more than a fifty cents coin, then it will not be excused. Salât will not be valid if it is not washed off.

If a najâsat-e-ghalîzah is thick and solid, for example stool or the excreta of fowls, etc. and its weight is equal to or less than about 4 grams, then performing salât without washing it off will be valid. But if it is more than this weight, salât will not be valid.

Najâsat-e-khafîfah falls on the body or clothing. If it is less than a quarter of the area on which it fell, it will be excused. But if it is equal to a quarter or more, it will not be excused. In other words, if it falls on one sleeve, it is less than a quarter of that sleeve. If it falls on one panel of a shirt, it is less than a quarter of it. If it falls on a scarf, it is less than a quarter of that scarf. Only if it is less than a quarter of all these it will be excused.

Similarly, if the najâsat-e-khafîfah falls on one hand or on a leg, then if it is less than a quarter of that hand or leg, salât will be valid if it is not washed. In other words, on whichever limb the najâsat falls, less than a quarter of that limb will be considered. If it is equal to a quarter or more, then it will not be excused. It will have to be washed. Salât that is performed without washing it will not be valid.

The water in which najâsat-e-ghalîzah falls also becomes najas-e-ghaleez; and the water in which najâsat-e-khafîfah falls also becomes najas-e-khafeef.

Impure oil fell on one's clothing but the extent of it was less than three centimetres in diameter. However, after some time it spread and became more than three centimetres in diameter. As long as it was less, it will be excused. But once it spreads beyond the limit, it will not be excused. Washing it off will be wajib. If it is not washed off, salât will not be valid.

The blood of fish is not impure. There is no harm if it falls on a person. The same applies to the blood of flies, bugs and mosquitos.

If a drop of urine equal to the eye of a needle falls, and it cannot be seen except after very careful examination, then there's no harm in it. It is not obligatory to wash it off, but to do so is preferable.

If a najâsat which can be seen, such as stool or blood, falls on the clothing, it should be washed until the najâsat is removed and no stain remains. There is no limit to the number of times it should be washed - the moment the najâsat is removed, it will become pure. The same rule applies when it falls on the body.

However, if the najâsat is removed in the first instance, it will be better to wash it two more times. And if it is removed in the second time, it will be better to wash it one more time. In other words, it is preferable to wash it three times.

If the najâsat is such that despite washing it several times and despite it being removed, the foul smell still remains or some stain is still there. Even in this instance, the clothing will be purified. It is not necessary to use any soap or detergents in order to get rid of the smell or stain.

If any impurity similar to urine which cannot be seen, falls on the clothing; then it should be washed three times. Each time that it is washed, the water should be squeezed out of it. After washing it the third time, the cloth should be wrung with full force - only then will it be purified. If it is not wrung with full force, the cloth will not be purified.

If any impurity falls on such a thing which cannot be wrung or squeezed, such as a bed, mat, jewellery, sand, utensils, bottles, shoes, etc., then the method of purifying these things is as follows: the item should be washed once and then the person should wait. When the water stops dripping from it, it should be washed a second time. When the water stops dripping, it should be washed a third time. In this way it will be purified.

If anything is thin and pure like water, it can also be used to wash off any impurity. If a person uses rose-water, or the extract of any herb, or vinegar; even then that thing will be purified. However, it is not permissible to use ghee, oil, milk and other similar substances which are sticky or fatty. That thing will remain impure.

Semen fell on the body or clothes and got dried. The body and clothes can be purified by scraping it off and rubbing it thoroughly. But if it has not dried as yet, it will have to be washed. But if a person did not wash himself after passing urine, and at that time semen came out; it will not become purified by rubbing it off. It will have to be washed.

If najâsat which can be seen, eg. dung, stool, blood, semen, etc., falls on one's shoes or leather socks, it could be removed and purified by rubbing it thoroughly on the ground. Similarly, it can also be purified by scraping it off. Even if it is not dry, and it is thoroughly scraped and rubbed off to such an extent that no sign of the najâsat remains, it will be purified.

If any najâsat like urine which is not seen, falls on the shoes or leather socks, then it cannot be purified except by washing.

As for clothing and the body, these can only be purified by washing. This is irrespective of whether the najâsat can be seen or not.

If mirrors, knives, gold and silver jewellery, copper, brass, steel, etc. become impure, they can be purified by wiping them thoroughly, or scraping them, or rubbing them with sand. But if these items have been engraved, they cannot be purified except by washing.

Some najâsat fell on the ground and got dried in such a way that there is no sign of it - there is no stain nor any foul smell of that najâsat. If it gets dry in this way, the ground will be pure. However, tayammum on such a piece of ground will not be permissible. However, it will be permissible to perform salât there. The same rule applies to bricks and stones that have been embedded with limestone or mortar into the ground in such a way that these cannot be removed except by digging them out. That is, once the najâsat dries and no sign of it remains, they will be purified, but tayammum will not be permissible.

Those bricks that have just been placed on the ground without being embedded with lime or cement will not get purified with the drying of the najâsat. They will have to be washed.

Grass which is growing on the ground also becomes purified with the drying and disappearance of the najâsat. But if the grass is cut, it will not be purified without washing.

If impure knives, earthen and copper utensils are placed on a blazing fire, they will also get purified.

There was some impurity on one's hand. Someone removed this najâsat by licking it off three times. It will become purified, but it is prohibited to lick it. A child vomitted milk on one's chest, and thereafter it licked the vomit and drank it up. The chest will be purified.

If an unused earthenware utensil becomes impure, and it is such that it absorbs the impurity, then it will not become purified by merely washing it. Instead, it should be filled with water and when traces of the impurity appear in the water, the utensil should be emptied. It should be filled again, and emptied again. This should be continuously done until no sign of the impurity remains - neither its colour nor its smell. Only then will it be purified.

The utensils which a potter makes with impure clay will remain impure as long as they are unbaked. Once they get baked, they will become pure.

Honey, syrup, ghee or oil became impure. Whatever the amount may be, add the same amount or more of water to it and keep it to boil. Once the water has evaporated, add more water and do the same three times. In this way it will get purified.

Alternatively, add the same amount of water and stir the contents. Once it comes on top of the water, remove it in some way or another. Repeat the process three times and it will be purified. If the ghee is gone hard, add water to it and heat it. Once it melts, remove it.

Clothes were dyed in an impure dye. It should be washed until clean water begins to come out of it. It will now be purified, irrespective of whether the dye comes out of the clothes or not. However it is preferable to wash it at least three times.

The ashes of dung-cakes, droppings of goats and other impure things are pure. Their smoke is also pure. If it comes onto one's bread, there is no harm in it.

One corner of a mat is impure and the balance of it is pure. It will be permissible to offer salât in the corner that is pure.

Land that has been plastered by dung is impure. Salât on it is not permissible without having laid some pure thing over it.

If the land which has been plastered by dung is dry, then it is permissible to spread even a wet cloth over it and offer salât. But it should not be so wet that some soil from that ground comes onto one's clothing.

After having washed his feet, a person walked bare-footed on some impure place and his foot-prints were visible on that place. His feet will not become impure. However, if due to the wet feet, the ground gets so wet, that some sand or impurity from that ground comes onto the feet; then they will become impure.

A person slept on an impure carpet and due to perspiration his clothes became damp. The same rule applies here, i.e. his clothes and body will not become impure. However, if they get so wet that some impurity from the carpet gets onto his clothes or body, they will be rendered impure.

A woman applied impure henna (mehendi) on her hands or feet. By washing them thoroughly until clean water flows out of them, the hands and feet will be purified. It is not obligatory to remove the colour.

A person applied surmah (antimony) or kajal (eye-pencil) which was impure. It is not necessary to wipe or wash it off. However, if it spreads and comes out of the eye, it will be obligatory to wash it.

If one applied impure oil onto one's head or body, then according to the normal procedure, it should be washed off three times. It is not necessary to remove it by putting soap or any such thing.

A dog put its mouth in flour or a monkey ate some of it. Whatever portion of the flour got dirty should be removed. It is permissible to eat the rest of it. If the flour was dry, then wherever its saliva is, that place should be removed. The balance of it is pure.

The saliva of a dog is impure, but the dog itself is not impure. So if a dog touches anyone's body or clothes, they will not become impure irrespective of whether the dog's body is dry or wet. However, it will be a different case if there is some najâsat on the dog's body.

A person passed wind at a time when his underclothing were wet. His clothing will not become impure by passing wind in such a state.

The clothes that got wet with impure water were wrapped with clean clothes. The wetness from the impure clothes got into the clean clothes, but no colour or smell of the impurity got into them. If these clean clothes got so wet that by wringing them one or two drops of water fall down, or at the time of wringing them, the hands get wet - then these clean clothes will also become impure. However, if they are not so wet, they will remain pure. And if the clothes that got wet with some specific impurity such as urine, were wrapped with clean clothes, then even if a little dampness or smell of those clothes gets into the clean clothes, they will also become impure.

A wooden plank is impure on one side and pure on the other side. If it is so thick that it can be sawed off in the centre, he can turn it over and perform salât on the pure side. But if it is not so thick, it will not be permissible.

A particular cloth is double-folded - one fold is impure and the other is pure. If both the folds are not stitched, it will be permissible to offer salât on the fold that is pure. But if both folds are stitched, salât will not be permissible even on the fold that is pure.