Well, I took mine out of the car, filled it with baking soda, and left it sitting outside for about a week. Still had a hint of nasty ciggy stink in it so I put a car air freshener in it. Now I can't smell it anymore.
You can order new ashtray inserts from a dealership. I almost had to do that. I, too, found the smell just gaggy and repulsive. I still can't believe how much I reeked when I smoked!