I did this a while ago, but I figured I'd post pics. I cleared the amber turn signals in my taillights.

Before:

http://i95.photobucket.com/albums/l147/lownoma18/Cadillac/taillightsbefore.jpg

I placed the light in the oven at 250 degrees for 15 minutes, and that softened the glue enough to separate the outer lens from the inner.

It looked like this:
http://i95.photobucket.com/albums/l147/lownoma18/Cadillac/taillight1.jpg

The yellow lens snaps right out:
http://i95.photobucket.com/albums/l147/lownoma18/Cadillac/taillight2.jpg

Clean the old silicone out of the channel and re-glue with black RTV

Final Product:
http://i95.photobucket.com/albums/l147/lownoma18/Cadillac/taillightsafter-1.jpg

Nice job! Really cleans things up back there. The main design complaint I have of all the Sevilles are their un-Cadillac-like rear lights. But that definately is a step in the right direction.

Did you purchase silvered amber bulbs as replacements? If not you should look into getting a set. They make the lights look truly cleared as you don't get the orange reflection when the lights are off, but still glow amber when in use.

I think getting the grey plastic behind the plate sprayed bodycolor would make the rest look more upscale as well.

i have clear bulbs in there right now, I'm not sure why the last pic looks amber, its just the photo.

these were taken a couple months ago, I actually painted all the gray plastic lower moldings and the license plate area green last week when I was repairing some accident damage.

I'm with you on the non-cadillac lights. My dad has a 99 Eldo, and the back end is so much better looking than my car