Leviticus 14:40

Then the priest shall command that they take away the stones in which the plague is, and they shall cast them into an unclean place without the city:

Leviticus 14:40 belongs to the special directions given by God to govern the service of Israel. Those directions made careful provision for preserving cleanliness among the people. This care is seen in the requirement that stones affected by the plague be taken away and cast outside the city into an unclean place.