If you really don’t want anyone messing with your coffee mug, this is the way to do it. Unless the person is feeling excessively brave, I doubt they’ll want to go anywhere near this one. It has painted on stains to make it appear as if it hasn’t been washed in quite some time. Of course you could make your own by not washing a cup, but this is probably a little more sanitary. You can purchase the Dirty Mug for $12 from Urban Outfitters.