Q: Is selling raw, salted pig skins for the leather industry halal as the Prophet sallallahu alaihi wa sallam said that any skin that is tanned is pure?
A: It is true that treated skins of animals become paak or pure and this is mentioned in the hadith, but this excludes the pig, because according to Shariah pig is najisul-ayn, i.e. every part of it is impure and can never become clean. (Hidaya, Raddul-muhtaar)
So it will be haraam to sell treated pig skins.