There are a few very small specs assumably under the glass of my iMac. Its white when the screen is of but it changes colors according to what is showing on the screen. What is it? And how can i get it out? 
It's a pretty easy thing to pry the glass off- so much so that I wouldn't be surprised if it were engineered for the end-user to perform this as a basic maintenance task. Dunno why Apple don't put a how-to on page 1 of the getting started booklet.
-iamthinking
Don't do it yourself! I tried and ended up with wayyyy more dust behind the screen than what was there before...not to mention the feeling like I tainted the machine all together by strapping a suction cup onto the glass and ripping it off. I ended up returning mine and getting another one...
The new one is perfect, but if a few pieces of dust get behind the glass, I'm just living with them this time.