The delivery person returned the order to the customer, but small pieces of food remained in his bag; he felt awkward about handing them over, unsure if the customer would accept them. Not everyone in this country follows the Islamic principle of eating in a way that leaves no leftovers.Is the delivery person required to pay for these pieces, or should local custom be the deciding factor?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

If those small pieces are merely minor leftovers that people do not customarily demand back – such as food scraps and the like – then it does not appear that the employee is obligated to pay for their price. Rather, this is something that is customarily overlooked. Perhaps this is what made the questioner feel uneasy about handing them over to the customer.

Lastly, we caution the questioner against blameworthy self-imposed hardship, and against intrusive whisperings (wasāwis) and dwelling on them, for this leads to great evil.

Allah knows best.