Among the conditions of prayer is to be clear of najas-filth in one's body, clothes, place of prayer, and what one carries in prayer, such as a bottle carried in one's pocket. If a najas-filth contacts one or what one carries, one's prayer is invalidated unless the najas-filth is dry and one throws it away immediately, or it is an exempted najas-filth like the blood of one's wound. One must remove an unexempted najas-filth with purifying water by removing the najas-filth and its properties, i.e., the taste, color, and odor.
The najas-filth without discernible characteristics (najasah hukmiyyah) is the najas-filth the color, taste, or odor of which cannot be detected, and it is removed by pouring water on it. The najas-filth of a dog or a pig is removed by washing the najas-filthy area seven times--one of which should be mixed with purifying soil. The washes which remove the physical presence of the najas-filth are deemed one wash even if they were numerous. In the case of using little water for removing the najas-filth, i.e., less than two qullahs, it is required to pour the water on the najas-filth. However, putting a najas-filth in an amount of water which is two qullahs or more will not make the water najas-filthy unless it changes it.
