Hall of Infinite Doors

You rummage through your pockets but you can't find anything. Refusing to be defeated, however, you use your sleeve to wipe the dirt and grime off the door handle.

Hmm, it's not going to win any art awards but it sure looks nice and clean now! Oh, but wait, the rest of the door also looks a little dusty. And so does the floor, and the walls, and the ceiling, and...

Eventually you find yourself going through the halls cleaning everything and anything you can find. Well, congratulations, you've become a top-rate janitor.