The Benz Vehicles with all the fancy controls on the steering wheel have a rubberized coating on the buttons-Anti slip coating. This Anti Slip coating from one week to the next will go from normal rubberized coating to a gooey mess in no time flat!!

Those steering wheel switches are in the three-figures for each set!! Not including removal and installation. It may set you back in the low four figures!! It pays to diy here...

What I did? Disconnected the battery.Removed the airbag. Removed the steering wheel. Removed the switches. Used this plastic cleaner from Eienszett

Plastic Deep Cleaner | einszett Car Care Products.

It was strong enough to soften the rubber coating, but not strong enough to melt through to the plastic like a solvent would. I cleaned it the rubber coating with a tooth brush and paper towel, Yet I wanted to try the Goo Gone(yellow liquid-which is designed to remove sticky decal residue), but I did not have any at hand, but Goo Gone is available at the 99cent stores.. Now my buttons have a shine like dash that has Amour All on it. That is way better than the bubble gum coating I had before...

Best of luck,

Martin