Extreme Makeover: Home EditionBy Rabbi Jack Abramowitz
A form of tzaraas could also appear in houses. After the Jews settled the land of Israel, they might find a red or green mark that would have to be shown to a kohein. The house would have to be emptied of its contents before the kohein arrived so that, if the house was declared unclean, those things would not be affected.
The kohein would examine the spot to see if the stain penetrates beneath the surface of the wall. If it does, the kohein would quarantine the house for a week, then re-examine it. If the spot has spread, the kohein would order the affected stones removed and discarded outside the city. The mortar around the affected area would be scraped off and similarly discarded. The stones would be replaced and the wall re-plastered.
If, after all that, the mark returns, the house is condemned. The stones and timber must be discarded outside the city.
During the time that the house is under quarantine, if someone goes into it, he would become ritually impure until nightfall. (He’d have to immerse in a mikvah.) If a person hung out there for a while, he’d have to immerse his clothes, as well. (The time frame is long enough to lie down or to have a bite to eat.)
If, after replacing the affected stones, the mark stays away, the kohein would declare the house clean. As with a human metzora, the purification process involves two birds, cedar, hyssop and crimson wool. The one bird is slaughtered over a clay pot of spring water so that the blood mixes in. The second bird and the other items are dipped in this liquid, which is also sprinkled seven times on the doorway of the house. The second bird is released and the house is declared clean.