Well used GMC and Chev pickups of the early 50's have always had sticky steering wheels in high humidity. I drove a 1950 GMC to school from 1958 until 1962. My hands were always black in high humidity. Lots of people bought covers for the steering wheels to fix the problem. Back in those days I didn't know of anyone who found a suitable paint to fix them. But of course, that was 50 years ago.