Leviticus 5:11-12

11But if he cannot afford two turtledoves or two young pigeons, he may bring a tenth of an ephah of fine flour1 as a sin offering. He must not put olive oil or frankincense on it, because it is a sin offering. 12He is to bring it to the priest, who shall take a handful from it as a memorial portion and burn it on the altar atop the food offerings to the LORD; it is a sin offering.