Custom Tail Lights
The first step in painting your tail lights is to decide on a pattern, then you need to cut the pattern out of paper, carboard, or I found that vinyl works great because of it's adhesive backing. Then once you've done this then you need to take out your tail lights as described below:
Click on pics below to enlarge
You will have to twist the plastic light sockets about a half a turn then they'll just pull out. Once you have your tail lights out clean them off very good and make sure they are completely dry. Then apply the design carefully so they are centered on both sides. For paint I used Krylon paint, made specially for plastic, no primer needed. The first coat should be pretty light, then put on another coat a little heavier, and finally put one more on just a little heavier then the previous. The next part it is crucial that you are VERY carefull! You have to peel off the design with out touching the paint, because you have to take the design off while the paint is still wet, otherwise it will peel the paint off your tail light. Try peel it from the center, not the edges, or you might screw up the edge of the design. Once it is off let your paint dry completely before trying to reinstall your tail lights (usually a couple hours or overnight is best). Then you can just reverse the process of removing them, just be carefull not to scratch your tail lights.
Dry your lights in a warm area, or under a heat lamp.
Before and after
Custom Dodge Neon taillights