02Audi-A4-3.0

I have a polyproplene car cover which was pretty cheap and works great. My buddy said that if my car is a little dirty, that the cover can actually haze or scratch my paint. Though my car is rarely really dirty I was just wondering if the cover can actually hurt my finish. I am also careful with the cover, putting it on the sunroof and then slowly pulling on it like a sheet on a bed. Good deal, Thanks!