A well known religious law says: "Everything is ritually pure for you unless you come to know that it is ritually impure." This law declares everything to be pure unless one becomes sure a particular item has become impure. And as long as you are not sure that it has become ritually impure (najis), it is to be considered pure and you can apply all the rules of purity to it without any hesitation or doubt.

The Ahlul Kitab (that is, the Jews, the Christians and the Zoroastrians) are ritually pure (tahir) as long as you do not know that they have become ritually impure (najis) by coming into contact with an impure object. You can follow this ruling when dealing with them.

The impurity transfers from one item to another through flowing wetness [that is, there is so much wetness in the impure item that it permeates to another item and makes it impure]. The impurity is neither transferred when it is dry, nor is transferred by non-flowing wetness. So, if you place your hand on a dry najis item, your hand will not become impure.

You can assume the ritual purity (taharat) of any person that you meet and shake hands with (even if that person's hand is wet) as long as you do not know his faith and religion - in such cases you can assume that he might be a Muslim or one of the Ahlul Kitab. Moreover, it is not obligatory for you to ask him in order to ascertain his religion; that is, even if doing so does not put you or him in any inconvenience. (See the question-answer section below).

Any water drops or other liquids that fall upon your body or dress are to be considered pure as long as you do not know that they are najis.

All kinds of alcohol (whether extracted from wood or other sources) is pure, not najis. So, the medicines, the perfumes, and the food containing alcohol are pure and can be used. It is also permissible to eat such food if the amount of alcohol is very minute.

No matter who was the previous user, the everyday commodities and utensils can be used without the need for purifying them as long as you do not know that they had become najis previously. (See the question-answer section below.)

If the carpet and the mattress become najis by the elements that do not have a mass (i.e., do not leave any marks or stains on the carpet or the mattress), it can be purified by sprinkling water over it from a kettle or a jug once until the pure water covers the impure area, and then wipe the water away by using a piece of cloth or a vacuum cleaner, etc. The carpet or the mattress will now be considered pure; and the water removed from it will be considered, on the basis of obligatory precaution, as najis.
The same rule will apply in purifying the cloth if it becomes najis by impure sources other than urine. Things becoming najis by urine will be discussed later on.

If one wants to purify the carpet or the mattress by using pure water connected to the kurr source [e.g., by using a hose pipe instead of pouring water from a jug], there is no need to wipe the water off using a piece of cloth or a vacuum cleaner, etc. As soon as the kurr water covers the najis area, it will become pure [and the water will also be considered as pure].

It is possible to purify the carpet or the mattress which has become najis by the elements that do have a mass (i.e., do leave marks or stains like blood or semen) by the same method as mentioned in No. 39 provided that the impure element is removed while washing or prior to washing. The only difference is that if it is purified by the qalil water [e.g., from a jug or a glass], then the water removed from the carpet will be considered najis as a confirmed opinion and not as an obligatory precaution.

If a carpet or a mattress becomes najis by urine of an infant child that mostly gets nutrition by breast-feeding, then it can be purified by sprinkling water - even if it is little - on it until it covers the najis area. In this case, there is no need to remove the water by using a piece of cloth or vacuum cleaner, etc.

If clothes become najis by urine, they can be purified by sprinkling little water on them from a kettle or a jug, etc., until it covers the najis area; then the water should be wiped off by using a piece of cloth, etc. You have to do this twice so that the clothes restore their taharah.
The water that has been wiped off from the clothes (while purifying it two times) will be considered najis on the basis of obligatory precaution, if there is no urine in them. Conversely the water will be considered najis as a confirmed opinion.

If one wants to purify such a clothes with pure water which is connected to a kurr source [e.g., under the water tap or by using a hose pipe], even then it is necessary to wash them twice. Similarly, it is necessary to wash the body twice -even when washed in kurr water- while purifying if it has become najis because of urine.

If the hand and the clothes become impure because of an intoxicating drink, a single wash can purify them. However, in case of purifying the same with little water, it is necessary to rinse the cloth after washing.

Utensils and cups that have become impure because of intoxicating drink should be washed three times if purified with little water. If they are purified with pure water connected to a kurr source, even then it should be washed three times, as a matter of obligatory precaution.

A single wash can purify the hand and the clothes that have become impure by licking of a dog. Such a clothes, need to be rinsed if it is purified by little water. (See the question-answer section below.)

Utensils and cups that have become impure by licking of a dog or by the dog drinking from them can be purified as follows: first they should be cleaned by using earth or dust, and then by washing them twice with water.