What insecticide is better?

Eggshell repellent cockroach method. Mash the waste egg shells, bake them to brown with slow fire, and grind them into powder. After observing the main passage frequented by cockroaches, sprinkle egg shell powder here, and cockroaches can avoid it when they smell it. (2) Boric acid cockroach killing method. Take a proper amount of flour, boric acid, onion and milk, chop the onion first and then squeeze it into juice. Add onion juice to the mixture of flour and boric acid, add a little milk, knead into balls with the diameter of 1 cm by hand, and put the balls of boric acid in places where cockroaches often haunt. Because cockroaches have a special preference for the smell of onions, they can eat meatballs as soon as they come up, but once they eat them, boric acid will dehydrate them and die;