Why coitinley! The method to use depends on where the rust is. If it is on parts that have non-critical dimensions, such as the butt plate, you can polish it off withemery cloth. I have shined up many a Mauser butt plate this way. However, if it is on the barrel or bolt, etc., you may want to use something less drastic, like a pad of 000 steel wool, or perhaps a piece of crocus cloth.

If you use steel wool, use some good solvent alongwith the elbow grease. Something like Shooters' Choice is good for assisting in removing rust.