What is the ruling on benefiting from postal interest funds, and is it permissible to use them to pursue a permissible academic diploma, or to distribute Islamic books as an ongoing charity (Sadaqah Jariyah) on behalf of a deceased person, or to give them only as charity to the poor?

Whoever has unlawfully acquired money, such as usurious interest, must, after repenting, spend it on the general welfare of Muslims, such as orphanages and Quran memorization schools, or give it to the poor. It is not permissible for him to spend it for his own benefit or on behalf of a deceased person, because whoever obtained this money does not originally own it. Therefore, it is not permissible for him to benefit from it or to dedicate its reward to anyone. This act is not described as charity.