Copper cleaning pad wooks the best for rust on a gun, a good quality lube could of avoided the rust. I hate to see things like this, It happens all to often, one time I used my kids 22 rifle at a friends property and when we were done shooting I leaned it up against a tree and forgot all about it. A couple of weeks later we went back there and the gun was still there, probably in worse shape then your gun. We cleaned it up pretty decent, but it's not the same afterwards. Every one makes mistakes.