What is the ruling on paying small sums of money (27, 150, 50 Riyals) owed to individuals who cannot be reached to charitable organizations, and should it be paid in one lump sum or in installments, and for which charitable causes?

The ease of obtaining something lawful does not exempt its recipient from returning it to its owner, nor is charity on its behalf sufficient if it is possible to deliver it to its rightful owner. However, if that is not possible, then let him give it as charity on behalf of its owner, and distribute it to the poor and the needy.