During a boat trip, I stored my sunglasses at the bottom of a bag, without a case, along with everything else. A spot of glue ended up on one of the lenses. I tried every gentle product I could think of : dish soap, alcohol wipes, but nothing worked. It was impossible to remove.
Yesterday, I forgot this pair of sunglasses in my car under the sun. They became very hot, and I noticed that the glue had started to bead. When I ran my finger over it, the glue came off easily.


You can look up the expansion coefficient of materials to see what will work well with that, freezing can also work too.