Just bite their heads off!
A cockroach can live for a week after its head is cut off. Its nervous system, or "brain," is scattered throughout its body, and thus its head is not really needed to stay alive. Cockroaches have been around for about 280 million years and can live a month without eating, but they need to drink water about every week. Since a cockroach can drink only through its mouth, a headless roach dies of dehydration within about a week.
Joe & Annette
2002 Monaco Windsor 40PBT, 2013 Honda CRV AWD