Yehezkiel 43:20

43:20 You will take some of its blood, and place it on the four horns of the altar, on the four corners of the ledge, and on the border all around; you will cleanse it and make atonement for it. ¹ 

Yehezkiel 43:22

43:22 “On the second day, you will offer a male goat without blemish for a sin offering. They will purify the altar just as they purified it with the bull.

[43:20]  ¹ sn Note the similar language in Lev 16:18.