That looks like the culprit of useing 90/100w bulbs. You really shouldn't go higher than 55watt in stock housings with out upgraded wiring anyways.
There are several thread where people have put the housings in the oven to soften the glue in order to open them up for either a reto-fit, repair, or painting.
Ill try to find you a couple real quick to help yea out.
Sent from 34.0764° N, 118.4296° W
Do one thing every day that scares you. -Eleanor Roosevelt