Clean and Unclean: Impurity of Objects

According to the Bible it is not just people or animals that can be impure but also objects. Objects are never unclean of themselves. They become unclean when they come into contact with unclean persons or animals.

A house that had come into contact with something unclean (such as the carcass of an unclean animal), had to be barred for seven days. After these days the unclean parts were removed and new plaster was used to cover the walls of the house (Leviticus 14:33-52).
Pots that had been touched by unclean people were smashed.
Clothes could also be unclean, for instance by being affected by mould. In that case the clothing had to be burned (Leviticus 13:47-59).

Objects made of non-flammable material could be purified by fire. Objects made of flammable material were cleaned with special “water for purification” (Numbers 31:21-24).