Today I noticed that "inside" the screen there is dirt on the corner of the screen. This is annoying when watching movies or using it with low brightness. So I just want to know is this a "screen leak" that allows the dirt to come in, or does it always happen (if it would be hardware I could send it back ;P). I use a case (you have to take the iPod out of it to use it), but it didn't seem to help. If it's normal, is there a way to clean it? Because I would need to open it up or something, right?