To erase initials from a watch case is a delicate job. If the letters are in the centre of an otherwise plain case, take a fine flat tile (costing about 4d. at a jewellers' material dealer), and, with short, firm strokes, file out the letters. Then go over the surface with a piece of enakestone or Tam-o'-Shanter hone, and finish with putty powder on a piece of soft leather. If the letters are in a small shield, the tendency is to damage the outside work, which would require to be re-cut. With a small riffler, or bent file with a flat surface, file out the letter's, dress with snakestone fashioned to a point, and finish as described above. If new initials are required, first draw them in pencil, and scratch them 01 with a point or etching needle. Then whet up a graver at moderately sharp angles, outline lightly, put in the thickening cuts, relieve the whole with light and graceful sprigged work, and then clean up.