Removing metal backs from glass earrings

Today I found the coolest earrings in the parking lot of the supermarket. It kinda looked as though they had been run over but the glass beads (a very pretty dichronic glass) were safe, the clip on earring backing however is pretty mangled beyond repair...which is ok as I don't wear clip-on's anyway. However now I must remove the metal back from the glass earring base. It seems to be glued on, but I have not idea what kind of glue. I was wondering if anyone has an idea about how I might attempt this. I would love to be able to glue some new posts on the back so I can wear them!