Ezekiel 43:20; Ezekiel 43:22

20 'You shall take some of its blood and put it on its four horns and on the four corners of the ledge and on the border round about; thus you shall cleanse it and make atonement for it.

22 'On the second day you shall offer a male goat without blemish for a sin offering, and they shall cleanse the altar as they cleansed it with the bull.