He—may Allah have mercy on him—was also asked:

“What is the ruling on pottery fired using impure substances, and on ovens heated with dung?”

He answered:

Praise be to Allah.

These questions rest on two principles. The first concerns using impure dung and similar substances as fuel to heat water or food and the like.

Some jurists among the followers of Ahmad and others said that this is impermissible because it involves handling and coming into direct contact with impurity. Others said that it is disliked but not forbidden, because destroying impure substances is not forbidden; rather, such use poses a risk of becoming soiled with them.

A similar case is using impure oil for lighting, since this is a use that consumes it. The well-known position reported from Ahmad and other scholars is that this is permissible, and this is what is transmitted from the Companions. The other position reported from him and others is that it is prohibited, because it poses a risk of becoming soiled with it, and because smoke from impure substances is disliked.

The correct view is that none of this is forbidden. For Allah Most High has forbidden foul things, such as blood, carrion and swine flesh, and it is authentically reported in the two Sahīh collections from the Prophet—may Allah bless him and grant him peace—