I have taken on a bathroom project...We moved into a home with a shower door attached to a stand-up fiberglass insert. I have removed the glass door; however, I cannot pry the frame from the shower insert. I removed the screws; however, a rubbery caulking is holding the metal frame onto the shower insert. How do I remove the metal framing without damaging the shower insert? Please respond as soon as possible as I have already begun working in this room. Thanks.