That will polish right out!! Get the serial number and gogle it,that will tell you what year it was made. Look up henry colectors . That should get you started theres a good market for them state side. All the inforemation you can get on it will help you get a good price. From your pictures it looks 80% there and the action not being jamed helps, clean it up some the "dirt and gunk" wipe it down with some light oil leave the patia ( helps to show age) rub off what you can of that green but dont shine it try some cola to wet your rag with. Ieave the rest as is ,would make a great wall hanger, or go hole hog and shine the p###$$ out of it!! Some one some where will love to have it what ever you do!