For Cockroaches: Rice + Sugar + Boric Acid
Cockroaches love warmth, crumbs, and dark corners. Mix equal parts cooked rice, sugar, and boric acid until you have a soft paste.
Shape it into tiny balls or spoon small amounts onto wax paper and place them behind appliances, under sinks, or along baseboards. The sugar lures them, the rice provides texture, and the boric acid quietly does the rest. Replace the bait every few days — you’ll see fewer roaches within a week.+

For Rats: Rice + Plaster of Paris (Powdered Gypsum)
Rats are smart — but this trick fools them. Combine uncooked rice and plaster of Paris in equal amounts, then add a bit of sugar or cocoa powder for scent. When eaten, the plaster hardens inside their stomachs, providing a humane and efficient result.
Place the mix in shallow dishes along rat trails — behind cabinets