How about a pic of the problem?
Depends on the depth of the scratch. 1k or 600 wet and dry is a good place to start if a good metal polish will not remove the damage, 600 can easily be polished by 1k and polished by metal polish, 3M, Maas or Mothers.
I like Novus, for scales. It will put a final polish on most scales, plastic, celluloid or horn. Novus comes in 3 grades, depending on the damage.