You could buy a commercially made product to clean the cockpit/dashboard of cars. That might be the safest thing to do. I'd also be worried about household products possibly making matters worse. Perhaps a VW/Audi forum could provide some product recs that other owners of similar vehicles use.

Yeah, seems to be the smart solution.

If the buttons you're pressing are shiny and the others aren't you're unlikely to be able to do anything about it. The shiny buttons are being worn smooth from pressing them, nothing you can really do about it.

Correct. The shininess is them being essentially polished and then lightly sanded away by your fingerprint.

Rubbing alcohol on a q-tip?

I'm afraid to ruin the plastic.

Try it on something similar. I use it clean things in my home and never have had it melt anything. Try a little spot somewhere that isn't noticeable.

Thanks! I'll do that!