I tend to start off with something like a screwdriver, prising the plastic up where it wraps around one of the metal parts. It doesn't matter whether the plastic bends or breaks, of course. I doubt it will be chemically stuck to metal, it will probably just be moulded onto it, so you work around the outside levering it away from the metal. After a while the chunks that would not bend far enough to release the metal, get broken off. If it is both very strong and rather flexible, you end up having to cut off the wrapped areas, with something like a very short saw - you probably have one of those on your multitool, but I use a sort of handle that mounts a broken off piece of hacksaw blade (I tend to have more than enough broken hacksaw blades, and I don't mind breaking them again).
