We started using "Mean Green" from the Dollar Store a few years ago, and it's incredible. It is a pretty aggressive cleaner, so be careful where you use it; sometimes I use it for really dirty sideart to take off the top layer of crud, then follow up with something milder like "Mean Green Glass Cleaner".
For control panels, I spray on Mean Green, let it sit for a few seconds and then use an old toothbrush to scrub. Nothing else I've used cuts through the tar and nicotine build up like Mean Green, and it's cheap as well.
Don't confuse it with Simple Green, which is okay but not nearly as strong and cost more.