You have to try this. It works. It works! It works !!!!
250g Boric Acid (H3BO3) in powder form - don't mix this up with Borax (Na2B4O7-10H20)
200g fresh onion pulp
20g starch powder
20g cake flour
Mix all the ingredients in a plastic bowl.
Spread out on an old newspaper (preferably in a garage or balcony or shed - cause this stuff stinks - but cockroaches don't mind it, in fact its the sugar and onion that attracts them - and its the Boric Acid that kills em) AND leave it there overnight.
Make fingernail sized balls of the paste. Wash your hands very very very well.
Please the balls all over, near drains, pipes, geysers, cupboards etc
Within 3-7 days your problem is gone! They start crawling out to die! Big favour I'd say, helps keep the recleaning of cupboards minimal.
Boric Acid is poisonous to some folk
This stuff is very very dangerous for little children and pregnant women.
Please share this recipe with your neighbours and everyone else!