Leviticus 14:5-7

5And the priest shall command to kill one of the birds in an earthen vessel over running water:

6as for the living bird, he shall take it, and the cedar wood, and the scarlet, and the hyssop, and shall dip them and the living bird in the blood of the bird that was killed over the running water:

7And he shall sprinkle upon him that is to be cleansed from the leprosy seven times, and shall pronounce him clean, and shall let go the living bird into the open field.