Epoxy is easy to remove with a bit of heat. I've done this hundreds of times with dichros and PBS cubes without losing a single one. As long as there is no plastic going in the toaster oven / oven, you'll be fine.
Bake the dichros/mounts at 170F for ten minutes or a bit longer if it is a big piece of alum. If there isn't too much epoxy, the hot dichros should pop off easily, otherwise gentle twisting or even a box-cutter may be necessary. Don't be afraid to rebake if necessary. Before anything cools, gently scrape off the epoxy from the dichros and then the mounts using a scraping razor. I prefer the long blade of a scraping razor as opposed to a box-cutter tool as the longer razor helps to prevent you from damaging the coating on the dichros. You can also remove the epoxy with your fingernail and that further reduces the chance of scratching your dichros. That said, even if you did make a little scratch on the dichros, it will likely be at the attachment point anyhow, so it isn't the end of that dichro.
Note that clear epoxy comes off the easiest. The dark / tougher stuff is a bit harder to remove.
Happy scraping!
-David
"Help, help, I'm being repressed!"