[DaRookie]

Is that the one with a hard encapsulation over the urethane?

If it is, then use a dremel with a cutoff wheel to get the hard stuff out of the way. Then I use a short utility knife to carefully slice the bottom urethane. Once the bottom is free you push out and can cut the sides free. The tension will ease the cutting.

Then I go outside and support the glass while slicing the top away.

HTH