[The ruling on manufactured leather]

The answer: It has not been narrated that the Prophet (May Allah bless him and his family and grant them peace), when he migrated to Madīnah, forbade them from using leather, water-skins, and vessels made from leather; he did not command them to discard them nor to replace them. And the scholars of the madhhab have said that this and the like of it, such as clarified butter and fat, become pure by the dominance of the Muslims over it. Based on this, whatever manufactured leather enters the lands of the Muslims is ruled to be pure.

Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2