Crumbs in the Silverware Drawer

I just don't understand it. I put my silverware in the dishwasher and turn it on. Once it is finished I open it up and I have shiny, sparkling silverware. I carry my silverware over to the designated drawer and place them in their slot. So, to my knowledge, the silverware is clean. But somehow, the next time I open up the drawer full of clean silverware there are crumbs in the silverware tray......... Why? How can it be? Are there crumb gnomes that come and sprinkle the crumbs in there when I am gone? This has to be one of life's great mysteries.