“Yahweh spoke to Moses. ‘Command the Israelites to put out of the camp everyone who is leprous, or has a discharge, and everyone who is unclean through contact with a corpse. You shall put out both male and female, putting them outside the camp. They must not defile their camp, where I live among them.’ The Israelites did so, putting them outside the camp. Just as Yahweh had spoken to Moses, so the Israelites did.”
Once again, Yahweh spoke to Moses, but without any indication of where. You have to expel males and females who are leprous, have a discharge, or have had contact with a corpse from the camp. The camp cannot be defiled because Yahweh is there. They are impure and unclean as was indicated in Leviticus, chapters 13, 15, and 21. In some cases, waiting until evening might make them clean. This appears to apply to those who will not wash themselves in the evening.