Cockroach balls made with boric acid. Don't put in places accessible to children or pets. Ingredients: 200g of boric acid; 1 medium onion (You can use onion flakes but they’re not as good); 1 cup of flour; 1/4 tsp of salt; About 100ml of milk.
Homemade Roach Killer To make a homemade roach killer, mix 2 to 3 tsp. of boric acid with equal parts of sugar and water to make a paste. Put it in the areas where roaches normally reside, and sprinkle it around the infested areas of your home. This method will eliminate roaches within two weeks.