Boric acid powder is a less toxic way to kill roaches than using roach spray. Many people believe that boric acid is not a roach poison, but it is minimally toxic. It should not be left in areas where people will walk over it and track it around a home. Instead, use boric acid only in the areas where cockroaches hide.
Sprinkle boric acid powder in locations where the roaches are likely to walk through it, such as behind and beside appliances. Put small amounts in the back corners of storage closets, garages and other places that humans don't often visit.
Create barriers with boric acid. A thin coating of boric acid powder that is placed in thresholds where roaches may cross can kill roaches that do come in. The trick to doing this safely is to place it on thresholds that humans will not walk through. The corners of the garage openings and any cracks in the side of the house that may allow cockroaches to come in are perfect places to lay this boric acid barrier.
Mix 1 teaspoon of boric acid with 1/4 cup of brown sugar and 1/4 cup of flour to make a roach bait. Sprinkle some into a jar lid and place where you have seen roach activity. The roaches will be attracted to the sugar and consume the boric acid.