Cockroaches are slim and can access your home through small cracks in your rook or walls, roof and laundry vents, and up your plumbing and sewer drains. These are places that most people don’t think about when trying to kill roaches on their own. Yet, the best defense against cockroaches is to prevent them from your home in the first place by keeping your kitchen and garbage areas clean. In some cases, where large infestations are involved, cleaning alone may not entirely solve the problem.