Hi Rod. To clean, or Not to clean. The age old question. Soft hair brushes, a photographer's lens brush (with the air reservoir), "Canned air"... I don't think I'd go much past that. Enameled surfaces can react strangely and possibly be damaged if you attempt to use any kind of cleaning fluid/cleanser on it. The Bavarian Military Merit Order, with it's exceptional deep blue enamel, is a beautiful piece from The Imperial German era and one you can be proud to own. Here's an example of the red case Rod is talking about. The Red ones are actually a bit harder to find than the blue!