How can money earned from a lottery-like subscription be returned to its unknown owners?

Lottery is a prohibited form of gambling. If the participants were unaware of its prohibition, then the money must be returned to its owners. If an owner cannot be reached, their money should be given as charity on their behalf. If the owner later appears, they are given the choice between having their money returned or accepting the act of charity. However, for those who participated while knowing of the prohibition, the money they paid should not be returned to them; instead, it should be spent on projects beneficial to Muslims or given as charity to the poor and needy.