Leviticus 4:25-26

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

26He must burn all its fat on the altar, like the fat of the fellowship sacrifice. In this way the priest will make atonement on his behalf for that person’s sin, and he will be forgiven.