Good, but the field of the flat files is not engraved and one cannot thus file fine notches in an outline of old key.
Advice from
Rasp and file buying guide
Finishing tool par excellence, the rasp is to the wood what the file to the metal. A surplus of material? No matter, with a few strokes your problem will be solved. Depending on their teeth or ridges, rasps and files can used to trim or finish a variety of materials.