Is it permissible to remove religious books containing innovations (bid'ah) from the mosque and replace them with other books free from innovations, even if the library is in a place designated for women? And is it permissible to replace them with several copies of a single book?

It is not permissible to endow books of misguidance, magic, and innovation (bid‘ah), and they must be removed. If there is a specialized student of knowledge who needs such books for his study and is secure from their evil, then it is permissible to give them to him or to endow them in a place designated for specialized students of knowledge. However, if there is no one who needs them, then they should be removed and destroyed. If the endowed books are beneficial and useful, but contain partial matters of innovation, then the endowment upon them is valid. In this case, if you destroy them, you must buy replacements, and it is permissible to buy other books that are more beneficial, and it is permissible to transfer the books to another mosque if the benefit from it is greater.