Stickies? No problem...solved in 45 min
Taking a tip from a friend, I tried Goo-gone. I poured liberal amounts onto a clean cotton rag with no fuzzies; it was an old t-shirt.
I started rubbing it on the center vents. I got no where and sat there bummed. I tried again and found that after the 15th or so stroke up and down, the stickies totally and completely wiped away to leave a perfect plastic finish. Brand new. Completely flawless. Keep turning the rag, keep adding the solvent. I completely cleaned all dash vents in 45 minutes. The only part i couldnt get was the dial that makes the vents turn side to side. I was even able to get the vents themselves, not just the panels thast surround them. Wear gloves or you will look like you washed your hands in shoe polish.
I am thrilled. Now my interior looks great. Cost? A sore index finger-tip.
Do it, it was simple. Let me know your results.
BTW I think Orange-citrus alcohol spraw will work just as well.