They vary depending on the maker, some are chalky, some are rubbery, some have bobble heads, but they ALL come with that grime filth layer that seems intentionally painted on.
If you’re curious, here’s what a clean one looks like.
It’s just hard plastic. (I glued sparkles to it…)
Go gently pet a circus peanut candy, it’s kind of like that.
That layer of intentional filth is ~antiquing~ and was A Huge Thing in the late 1960s into the 1970s–loads of furniture from that era has it, too.