Leviticus 14:4-6

MSB(i) 4 the priest shall order that two live clean birds, cedar wood, scarlet yarn, and hyssop be brought for the one to be cleansed. 5 Then the priest shall command that one of the birds be slaughtered over fresh water in a clay pot. 6 And he is to take the live bird together with the cedar wood, scarlet yarn, and hyssop, and dip them into the blood of the bird that was slaughtered over the fresh water.