Just wondering what to do about this/if i'm seeing things/whats going on. So, i've had my new imac for 3 weeks, yet today I notice in the bottom right and left of the screen there is a grey smudgey mark; akin to a finger print, or the kind of impression that you get if the lamination is coming off a car windscreen, but very faint. Easily noticeable if you put a white background on. So... what to do? Is this common?