TSK · Exodus 29:35

For seven days you are to make atonement for the altar and set it apart as holy. Then the altar will be most holy. Anything that touches the altar will be holy.

“You are to bring Aaron and his sons to the entrance of the tent of meeting and wash them with water.

The Seven Days of Purification“The one being cleansed must then wash his clothes, shave off all his hair, and bathe in water, and so be clean. Then afterward he may enter the camp, but he must live outside his tent seven days.