To go back to the original question, if I saw a gun in that condition, I'd pull out my cell phone and call the police. I would try not to handle it, in case it had been used in a crime and there were prints on the gun. If I was in a very rural area where it would take too long to wait for a police response, then I would retrieve the firearm, unload it, and then call the police.
Jared
Jared