Leviticus 14:30

Then the priest shall put some of the oil that is in his hand on the tip of the right ear of him who is to be cleansed, and on the thumb of his right hand, and on the big toe of his right foot, on the place of the blood of the trespass offering.

The rest of the oil that is in the priest's hand he shall put on the head of him who is to be cleansed, to make atonement for him before Yahweh.

even such as he is able to afford, the one for a sin offering, and the other for a burnt offering, with the meal offering. The priest shall make atonement for him who is to be cleansed before Yahweh.

This is the law for him in whom is the plague of leprosy, who is not able to afford the sacrifice for his cleansing.