Is it possible that those splotches some are seeing at the bottom of the screen are simply smudge marks left over from the processing plant caused by the way it was handled on the assembly line?
If that is the problem, perhaps this product can remove them:
http://www.amazon.com/PixelClean-Wet...=IE5J3AN7J4KP3
I use them on my other Kindles to remove finger print marks and on all my LCD TV's and gadgets.