anyone know how to clean 'gummy' control buttons on wheel? it's almost like a film has formed on there and it's sticky to the touch. this is the standard 'rubber' steering wheel on a '01 CLK 430
thanks

 

I have the same problem with 2001 E320. I decided to try and remove the coating. First i used a citrus solvent which softened the coating, then I carefully scrapped the coating off using my finger nail. This is a slow process since the softened coating wants to stick to the switch. After I had most of the coating removed except for a sticky film, i used rubbing alcohol on a cloth to remove the remaining residue. So far i have completed one of the 4 switches. Be very careful of avoid getting the solvents (primarily the alcohol) on the soft center (air bag padding) since it will take the color off. The cleaned switch turned out great. Be patient, it is a slow process. I am sure there are other solvents that would work but avoid any that could attack the plastic switches. Good Luck. I make no guarantee that this will work for you. Proceed with caution. Apply solvents with soft cloth slightly moistened to avoid any solvent running into spaces around switch.

 

Its a common issue switches are in stock and can be replaced by just removing the airbag. They good willed mine!