I had a similar problem with a
Vauxhall Cresta I owned a few years back......
I don't know what causes it,but I eventually gave up and repainted the wheel to match the car.
It seems to be a humidity thing but it feels awful,plus your hands get pretty black too.
Bad if you're heading out for the evening..... Especially if you've just spent half an hour getting all the crud from under your nails and removed about three layers of skin trying to make your hands look in some way presentable!