^ That only works if its on the outside of the light and it can be done with some rubbing compound, some fine grit sandpaper and time.

If its on the inside unless you bake the light in the oven to get the glue soft enough to get the lens off it wont do you any good.

I do recall I once had a headlight for an atv that was similar in the way it was made like a car. I tried backing it but it wouldnt budge, finally got out the dremel and cut it apart at the seam. I just reglued it with some clear silicone when I was done.