To make a roach killing paste, mix 3 teaspoons of boric acid with 3 teaspoons of sugar and 3 teaspoons of water. Mix thoroughly, and store in zip-style plastic bags to retain the softness of the paste.
Recipes can also contain other ingredients to attract roaches. Heloise's recipe for boric acid balls requires 8 ounces of boric acid, 1/8 of a cup of sugar, 1/2 of a cup of flour, 1/2 of an onion, 1/4 a cup of shortening and enough water to form a dough. Mix the shortening and sugar, and then mix the dry ingredients into the shortening. Add the water, and form small balls from the dough. The dough can be placed anywhere in the home to kill roaches but should be placed out of the reach of children.
Peanut butter can also be used to make a paste that kills roaches. Mix a cup of 5 percent boric acid with a cup of sweetened peanut butter, then add enough water to make a paste. Honey may be used to sweeten unsweetened peanut butter. Add about a teaspoon of honey to the mixture to attract the pests to the bait.
Any type of sugar, including corn syrup, honey or molasses, can be used with water and boric acid to make a paste. The boric acid content should be equal to the amount of sugar used. When using liquid sweeteners, reduce the amount of water used to ensure the mixture is the proper consistency.