My experience is counter to the advice given above regarding Awlgrip.
I've used fleece covers on my Awlgrip II paint for 7 years. They have not caused any harm and IMO have protected the paint better than uncovered fenders which I have seen leave rubbery streaks after heavy use/weather.
The rubber streaks are easily removeable, but why bother?
I found them online be googling "fuzzy fenders" and adding "-zz top" so that I didn't get a bunch of unrelated, but very funny coincidental guitar pictures.