Combine the following items to make a paste.
1 cup borax
1/4 cup granulated sugar
1/4 cup chopped onion
1 tablespoon cornstarch
1 tablespoon water
Carefully roll into small balls and Place 2 or 3 balls into a sandwich baggie, leaving the top open. Carefully place these balls wherever the roaches may roam. They will eat them and die.
CAUTION: Hide these bags so that children and pets can't get at them as they contain ingredients that are not safe for either.