my personal tips for roach control:
1) keep foods and organic material in airtight containers.
2) minimize storage of organic waste
3) control ingress points by covering kitchen and bathroom sink and drainage holes
4) start the extermination process early - if possible, when you mostly see nymphs. If you see full grown roaches it means they've likely started to breed. It takes 6-12 months for cockroaches to reach sexual maturity and they will live for at least another year.
5) maintain general cleanliness/hygiene.
6) if you see a live one, the fastest and cleanest killing method is actually diluted dishwashing liquid. Always keep a spray bottle of the stuff handy. They work faster than common insecticides and are cheaper too!

faster than cockroach spray as long as not overly diluted. Most important is you must spray enough to cover and wet their entire body (basically soak them), the idea being that you want to clog their breathing holes and suffocate them.

ps. I've not tried before but maybe you can use a super soaker gun and fill it with dishwashing liquid

This post has been edited by oe_kintaro: Nov 3 2014, 09:17 AM