How to Kill Roaches With Alcohol. Cockroaches can be hard to kill (they can survive without their heads for up to 3 days) and difficult to control once an infestation starts in your home. However, you can kill these stomach-turning invaders with rubbing alcohol.
Fill a squirt bottle with rubbing alcohol. Use a squirt bottle with a tight spray or a stream setting as opposed to a loose spray that goes everywhere. Never reuse a squirt bottle that previously contained a different cleaning product.
Squirt any invading roaches, making sure you hit the roach dead on and completely cover it. Roaches breath through their holes, called spiracles, in their hard shells. Squirting rubbing alcohol onto the roach will fill up the spiracles and suffocate them quickly.
Clean up the roach corpses so other roaches aren't attracted. Roaches actually feed on roach corpses.