There are two ways to kill a cockroach, one way involves the same way to prevent its intrusion in the first place: starvation. If we don’t have food or water sprinkled all over our floors and in the cracks of our sofas, they won’t last more than a month and they probably won’t move in to begin with. The second way is with poison.
Cockroaches poop and pee and make our houses stink. Outside, they keep the world clean because the rain cleans up after them. They’ll only visit to clean up houses whose keepers don’t clean up after themselves.