Is the customary village practice of replacing a tin of olive oil with another tin after the harvest considered usury (riba), according to the hadith "hand to hand" (yadan bi-yad)?

What you are doing, by taking a tin of oil or other known measures, and returning the equivalent after a period, is a recommended loan (qard mustahabb) because it relieves the distress of Muslims and fulfills their needs. It is permissible for anything that can be measured by weight, volume, count, or description. This is based on the Prophet, peace and blessings be upon him, who said: "Whoever makes an advance payment for dates, let him do so for a known measure and a known weight until a known term." The Prophet, peace and blessings be upon him, himself borrowed and was excellent in repayment. This act, God willing, carries a reward.