Reverse lights

Ok so for the past year or so my reverse light has been out. Today i decided to take it off and c whats up. I look inside to find that all the reflectiveness has been replaced by some sort of black cakaed on material that refises to come off. I need to know if i can sperate the plastic glass from the back moutning assembly without the "water proof" seal being broken for ever.
2001 Grand AM SE.

I am not sure if you can seperate the lens from the housing, but if you can and the seal gets messed up you can buy a tube of silicone form-a-gasket at the local parts store to replace the factory seal.

I had to repair a headlight assembly on my 98 Montana...I was able to seperate the lense and housing but had to use the form-a-gasket when I putit together, it worked out fine I had a good seal and had no problems with moisture getting in.

Hope this helps,

Ohh it does. Now i need to make sure that i don't break the plastic.
Thanks a bunch.