Leviticus 4:25-26

25Then the priest is to take some of the blood of the sin offering with his finger and put it on the horns of the altar of burnt offering; and the rest of its blood he shall pour out at the base of the altar of burnt offering.

26And he shall offer all its fat up in smoke on the altar like the fat from the sacrifice of peace offerings; so the priest shall make atonement for him in regard to his sin, and he will be forgiven.