If you are trapping spring beavers, and you don't want to mess with the castors and oil sacks, I'd give you "store credit" on anything I sell at conventions for them. You don't need to clean them up or dry them or anything, just cut them out with the oil sacks all in one and toss them in a dish with a lid or freezer bag in the freezer. You can bring them to me frozen. I don't have a way to tell you just what I'll pay, all that will depend on what you got. I don't need a ton of them either so no big deal if you only have 5-6 beavers worth I'd still like to have them, better than just tossing them out with the carcasses.
Shoot me a PM if you are interested in a trade and I'll try to make a deal we can both be happy with.