Soap is not to be deemed impure on the basis of doubt

Question

Regarding the scented bathing soap and laundry soap produced in factories, it is heard that pig fat is compounded into it, and that [the fat] is converted into salts by a chemical reaction and mixed into the soap. Is it permissible to use it or not?

Answer

The fat of carrion is impure, and the pig is impure in its very essence (najis al-'ayn). As long as a transformation of essence (qalb mahiyya) has not taken place, whereby its reality and properties change, use is not permissible. [But] without verification, on the basis of doubt, there is also no right to call the soap impure.

Source: Fatawa Mahmudiyya

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