When you empty the last couple of ash trays, put those butt's in a jar with a screw on lid, pour in some water, make it nice and gross, then just put it under the sink or something.

When the cravings get really bad go get that jar, and have a good look at it, imagine that crap going into your lungs, then open it up and take a whiff, shit its gross, but those cravings are gone in a flash, works like a charm.

Keeping a pen or something to chew on sometimes helps as well.

Good luck bro.