DO NOT USE THINNER!
I did it based off the recommendation in one of the interior threads and it fucked my dash. Just use a pressure washer and be very patient as it will take a while. I used thinner and it stripper it off very quickly, but it turned it white, almost "dried out" looking. I ended up having to paint mine.
hahahahahaha, trolled. degreaser can turn plastic, what u think thinner is going to do?....