Leviticus 14:4-7

4then the priest shall give orders to take two live clean birds and cedar wood and scarlet string and hyssop for the one to be cleansed.

5Next the priest shall order that one of the birds be killed [as a sacrifice] in an earthenware container over [fresh] running water.

6As for the live bird, he shall take it together with the cedar wood and the scarlet string and the hyssop, and shall dip them and the live bird in the blood of the bird sacrificed over the running water.

7He shall sprinkle [the blood] seven times on the one to be cleansed from the leprosy and shall pronounce him [ceremonially] clean. Then he shall let the live bird go free over the open field.