Leviticus 14:4-7

4the priest shall command them to take for him who is to be cleansed two live clean birds and cedarwood and scarlet yarn and hyssop.

5And the priest shall command them to kill one of the birds in an earthenware vessel over fresh water.

6He shall take the live bird with the cedarwood and the scarlet yarn and the hyssop, and dip them and the live bird in the blood of the bird that was killed over the fresh water.

7And he shall sprinkle it seven times on him who is to be cleansed of the leprous disease. Then he shall pronounce him clean and shall let the living bird go into the open field.