What is the ruling on accepting money given by donors for charitable work without it being solicited, and is it permissible to use it to pay off debts?

It is forbidden for an employee to accept gifts from donors, because such gifts are considered among theworking-gifts that Islamic law has prohibited. This is supported by the agreed-upon Hadith (definition) narrated by Abu Humaid Al-Sa'idi, in which the Prophet, peace and blessings be upon him, said: "What is wrong with a worker whom I send, and he says: 'This is for you, and this was given to me as a gift'? Why did he not stay in his father's house or his mother's house and see whether he would be given a gift or not?"