Well after tons of searching on this site as well as the www, I have found a solution to my sticky/gunky button problem in my 08 GT. The parts are: Patience, some DIY know how for disassembly and reassembly of internal parts and... Turtle Wax Bug and Tar remover. Check out the before and afters...
I created a PowerPoint presentation on DIY instructions for removing the radio / radio buttons / other control panels and buttons.
Hope this helps people out.