What is the type of earth and ground suitable for dry ablution (tayammum), and how can an ordinary person distinguish it and know if it has been industrially processed? Is it permissible to perform tayammum with dust found in the street, or that collected after sweeping a house, or found in a vacuum cleaner bag? What is the sufficient quantity for tayammum? And how can one perform tayammum with dust given concerns about health risks and disease transmission, especially when water is unavailable for washing hands afterward?

According to the Hanafis and Malikis, "al-Sa'id" refers to the surface of the earth, and this is the prevailing fatwa (definition). Sand, dust, and stones are considered part of al-Sa'id, whereas red bricks, wood, and iron are not. It is permissible to perform tayammum (definition) with dust from the street, the house, or that found in a vacuum cleaner, provided it is pure. There is no specific quantity of dust required; it is sufficient to strike the hands on the al-Sa'id and then wipe the face and the palms of the hands. Tayammum while in residence due to lack of water is hardly applicable, and some scholars oblige the person who performs tayammum while in residence to repeat the prayer. It is not necessary to inhale the dust or to put it into the mouth and nose. The dust is removed from the body after tayammum by shaking it off the face and palms.