I know you said "not to remove it" but 3 nuts and I removed one of mine, pressure washed it, wiped the heck out of it with water and terrycloth and it feels and looks like new.

The "sticky" feeling is from it sitting in the sun for too many years. It happens on every steering wheel and it goes away with elbow grease. Made a few auto-wrecker wheels feel like new, just have to clean it about 3 times to get it like new again.