Thank you, ladies! I'll try the Henry Ford village. They may be able to lead me to a solution.
I wish that the glue had been applied in the 80's but it wasn't. It was already glued to the board when my grandmother purchased it and had been for quite a while. The glass that was in the frame had small bubbles and was very wavy- indicative of early glass. I would guess it had been framed in the early 1900's by the wood, frame style and glass. The frame was made for the quilt.
I think you are correct, Cheryl, I should just leave it as is and enjoy it.
Karin