Connect a hose from ur car exhaust to the inside of ur car....Turn on the engine n let the exhaust for say 1-2 hr (of course make sure u not in the car la during tat time).......this should kill/poison the living cockroaches with carbon monoxide......after tat turn off the engine n air ur car(open windows n doors) for bout half a day b4 using ur car again.

Voila, cockroach dead. No need pandan leaves.