How can one get rid of money later discovered to be unlawful, what is the ruling on the portion of it that was disposed of before knowing its unlawfulness, and must it be compensated?

The money for which one is accountable falls into two categories: Either it belongs to known individuals, in which case it must be returned to them. If it is impossible to reach them, then it should be given as charity on their behalf. Or, it is money that cannot be returned to its owners, such as usurious interest. In this case, it is not permissible to leave it with the bank. Rather, the repentant person must spend it on charitable causes without benefiting from it himself or for those he supports. As for what was spent before knowing of its prohibition, there is no need to compensate for it.