I don't know as much about chrome plating as Chrome Dynamics but I do know restoration techniques. Paint and sandpaper is NOT the best answer.
I know that paint doesn't stop rust and you shouldnt use sandpaper on chrome. Buffing out your scratches will annoy most platers and add to the expense. If you want to remove the rust before you store the chrome use naval jelly. Oil will seal it better than paint. It costs less and is quicker.