Hawzah News Agency – In view of the use of brushes in painting and sketching, and considering that good quality brushes are imported from non-Islamic countries and are often made of pig’s hair and are accessible to all, especially in cultural and propagational centers, what is the legal rule regarding using such brushes?

Answer: Pig’s hair is najis and its use is not permissible in situations where purity is required by Islamic law; but there is no problem in using it where purity is not necessary. Further, if it is not known whether the brush is made of pig’s hair or not, there is no problem in its use even in cases where purity is required.

Source: https://www.leader.ir/en/book/32/Practical-Laws-of-Islam