Is it permissible to give as charity the value of money that has been mixed with private funds or has not been returned to the shop, given the inability to return it directly to its owner?

It is not permissible to give the money of the shop owner as charity unless one despairs of reaching him. It is obligatory to deliver his right to him, even through indirect means, or to seek his forgiveness, for the Prophet, peace and blessings be upon him, said: "The hand is responsible for what it has taken until it returns it."