Ants in your pantry? Stalk them and seal off cracks where they are entering with putty or petroleum jelly. Try sprinkling red pepper on floors and counter-tops.
Roach poison: Use 2 parts flour, 1 part Boric Acid Power, and ½ part sugar. Mix well or sift. Sprinkle or dust it (using a narrow-spouted plastic squeeze bottle) into moldings and crevices. This kills them slowly but surely (six days or longer). They will not develop a resistance to it. Boric Acid is not absorbed by your skin or inhaled, but it is poisonous if eaten.