Sayyed Mohammad Al-Musawi, Sayyed Mohammad al-Musawi is originally from Iraq and heads up the World Ahlul Bayt Islamic League in London. Other than being involved in various humanitarian projects, he frequently responds to... Answered 3 years ago

You must do every thing you can to return the money to its owners either directly to them or to their inheritors if they are dead.

If you tried your best and could not reach to them, then it must be given to the Marja' of Taqleed who will distribute it to the poor as Majhool al-Maalik (unknown owner) on behalf of the real owners.