The green frame does come off. The top edge and bottom edge should be able to be wiggled free, but the center (near the mute button) will be the difficult part. What I did was lift the top and bottom edge off and apply direct pressure to the center part. It did take quite a bit of pressure before it popped off. Once it does, you will see why. There is a plastic tab that fits in under something else that is holding it on...It will likely go back together tight just fine.

However, I'm not at that point yet. I'm with CV27 trying to figure out what it is that I'm supposed to clean in there...there doesn't appear to be much to do. And, my screen still doesn't do anything.

-Kevin