Leviticus 5:11-12

11‘But if he cannot afford to bring two turtledoves or two young pigeons, then he shall bring as his offering for his sin the tenth part of an ephah of fine flour as a sin offering; he shall not put [olive] oil or incense on it, for it is a sin offering.

12He shall bring it to the priest, who shall take a handful of it as a memorial portion and offer it up in smoke on the altar, with the offerings by fire to the Lord; it is a sin offering.