I have a Winchester rifle, given to me by my father, who had recieved it from his father. It is a Winchester 1894 .30-30, pre-1960's. I have no idea when the firearm was made, as it is nowhere on the weapon. It is entirely original and intact, with classic blueing, furniture and leather sling. I have noticed on the reciever there is some sort of substance on the weapon. I thought it was rust at first, but nothing I cleaned it with seemed to work. I keep the weapon very clean, but I found it still won't come off. I would deeply appreciate some help on this matter - and a picture is up. If you would need another picture, please tell me. Thanks!