There is a very small dent on the top of my unibody MacBook. When running my finger across it, it just feels like it can slide down a bit and then back up. It's extremely tiny but still somewhat annoying to look at. I've never dropped/hit the case so I have absolutely no idea how this would happen. Is there anything I can do? I mean, it looks like a really, really minor smudge but it is still annoying to have to know is always on there.