I have had only limited success removing the oils and smudges from one's fingers that are deposited around the knobs and buttons on my dashboard. You know, those little smudges on the fan up/down buttons. I not quite sure if it is just oil or sometimes just the matte plastic being worn smooth. I've had mild success with IPA but I've never wanted to press the subject too hard and possibly remove the print or diagrams on these buttons.
Suggestions?
Suggestions?