A simple and effective solution to get rid of cockroaches for good and with no usage of chemicals is to get some bottle caps and fill them with 50% baking Soda (Bicarbonate of Soda) and 50% powdered sugar.
sugar attracts the roaches and soda kills them.
As these bugs are hard case insects they will eventually explode from their own gases.
Fill the caps every year.
Simple and very effective baking soda and powdered sugar :D