Rear combination light taking on water

I searched all over but couldn't find anything about this. my driver's side light started taking on water during the last major storm. enough to almost cover the reverse light. i know how to take the assembly off the truck, but does anyone know how to remove the clear lens from the housing so i can dry it out and replace what i'm assuming is a bad gasket? i tried putting a flathead in between the two pieces, but only managed to slightly crack the lens.

 

It's sealed with glue. I would drill a hole, drain, add silica gel, reseal the entire lens.

 

I'd try similar to the BHLM and bake it ever so slightly.