I moved back into the family home many years ago. Old home and tons of roaches. I tried a lot of commercial products with limited success until I used Boric Acid. Very cheap and very effective.
Cockroach report - I tried boric acid mixed with icing sugar a few days ago and now I can hardy find a roach anywhere. I also filled up cracks in the kitchen cupboards with expanding foam sealant. Thanks for the tip guys. I just hope they don't adapt or mutate...