It certainly APPEARS to be a Springfield "trapdoor" M1877 Carbine, but which version requires more info; you can probably do a search for Springfield trapdoor and get all the info you'd ever need or want. I'd suggest not doing ANYTHING in the way of "cleaning it up", since it could easily be worth some serious money. There SHOULD be a serial number on the top of the receiver, at the rear of the lift-up "trapdoor", with a model number at the front of the "trapdoor" itself. HTH.