Leviticus 4:18

4:18 He must put some of the blood on the horns of the altar which is before the Lord in the Meeting Tent, and all the rest of the blood he must pour out at the base of the altar of burnt offering that is at the entrance of the Meeting Tent.

Leviticus 4:34

4:34 Then the priest must 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 he must pour out all the rest of its blood at the base of the altar.