a friend has gave me an nef r92 22lr with 4inch barrel to fix, its fine mechanically but it has specks of rust everywhere. even down in the crevices, and the cylinder has a few small holes in it from the rust. i thought of using a wire cleaning brush with solvent and oil then just blue it. however i have heard of permatex rust treatment that destroys rust then coats the metal to protect it. with the cylinder like it is i'm leaning toward permatex but i haven't used it before. what do ya'll think? thanks