[laidman]

an oven is a good start but for better control, and more heat right where you need it I wouldd us a paint stripper as noted above. If you are looking for a complete How-to please see : http://www.focusfanatics.com/howtos/resealingtaillight/
or just do a google search, there are quite a few of them but all give the same info. Have a ball. Don't get too rammy and break it ......