Rashi on Leviticus 14:40/רש"י על ויקרא י״ד:מ׳

1וחלצו את האבנים — Understand וחלצו as the Targum does: וישלפון, i.e. they shall remove them from there. It is similar to, (Deuteronomy 25:9) וחלצה נעלו— which is an expression for removing ("she shall remove his shoe”).

2אל מקום טמא UNTO AN UNCLEAN PLACE — i. e. a place where clean things are not likely to be handled. Scripture teaches you that these stones make the place where they are deposited unclean for the time they are there.