First of all, please do this AT YOUR OWN RISK. If you melt or destroy your car parts, we will not be responsible in any way. If you burn your body parts, like your hands or arms, you have not excersised proper care,
So having said that, here is the baking recipie for plastic headlights. Might work for glass ones or even taillights. Check that the sealant is black.
You also may wish to try to do this in smaller temperature increments, starting from the lower setting and slowly increasing, especially if you are doing the tailights, they were not designed for high temperatures.
It is also advisable to do it together with someone to help you out, especially when you are opening the lights.
-Make sure your lights are clean
-Do one light at a time
-Make sure that four of the clips that keep lens and housing are off
-Make sure that all metal parts, screws, adjusters and brackers are off
-Make sure that all wiring and bulb is out
-Pre-heat the oven to 200-220F
-Make 3 or 4 balls out of aluminum foil
-Place foil balls on a cookie sheet under the headlight
-TURN OFF THE OVEN
-Place cookie pan with ONE of yours light inside on foil balls so no headlight part touches the cookie sheet
-Wait 5-8 minutes for headlights to fully heat
-Gently pry the lens off the housing with something wide, like table knife, do this around the most of the circumference of the light
-DO NOT PULL AT AN EXTEREME ANGLE, you will crack the housing
-The black sealant that the headlights are sealed is very sticky an runny when heated, so make sure you do not get it on the parts you do not want to be ruined. Use someone's help with a knife to cut the glue strands and keep them back.
-If not coming off, try heating longer
-You can do up to 250F and 10min
-NEVER heat a headlight in an oven with an oven being turned on
-Use OVEN MITTS so you do not burn your hands/arms
Mine worked after 8 minutes at 220F. If your lens is glass, so be careful, not to crack. Also the housing if fairly brittle, but repairable, so be careful.
Good luck.