Is it permissible to dispose of usurious profits of unknown origin by spending them on the expansion of a mosque?

It is obligatory to calculate and determine the usurious profits. If this is not possible, then it is permissible to estimate them based on strong presumption, while prioritizing caution. One must then dispose of these profits by spending them on general Muslim welfare, such as building bridges and establishing schools. It is also permissible to donate them for building mosques.