Anything that the dead body of one of these animals falls on becomes “unclean.” If it is an oven or cooking pot, break it. It is “unclean.” And you must consider it “unclean.”
But a spring or a well for collecting water remains “clean.” That is true even if the dead body of one of these animals falls into it. But anyone who touches the dead body is not “clean.”
The priest must burn everything with the mold in it. He must burn the clothes or the woven or knitted cloth made out of wool or linen. He must burn the leather goods. The mold destroys. So everything must be burned.