Leviticus 5:11-13

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. 13In this way the priest will make atonement for him for any of these sins he has committed, and he will be forgiven. The remainder will belong to the priest, like the grain offering.”