I'm a retired Navy Chief. Coffee mugs are sacred terriroty, never to be washed, only to be rinsed and put away. So imagine if you found my mug, washed my mug, and I discovered it just before using it. I've attached the photos Rallypoint friends, get creative and let's get this post to go viral!
That is a navy thing which I fully understand. However, the in the army the Soldiers in the field have a canteen cup whuch the cup is never polished. It is not tradition which the navy has many fine traditions. It is meant for the cup not to be reflective; camoflouged, security measure.