Whenever food and water are easy to find, roaches will invite themselves to dinner. Meticulously clean your kitchen, including crumbs near the stove, microwave, and refrigerator. Vacuum scraps of food from corners and around the cabinet bases. To paralyze and eventually kill roaches, mix boric acid with water and flour, and place in jar lids in the back of cupboards and underneath stoves. (Caution! Keep out of reach of pets and children.) The flour will attract the roaches; the boric acid will eat away at their exoskeleton.