try rubbing alcohol on the edges that have dirt with a Q -tip, i buff clear bra with
menzerna 106ff when cloudy comes out great , other than that, heat up film with hot water or a heat gun on low then pick and peel then remove film fully then residue with a prep solve,
the only problem could be if it was a repaint not properly painted and you will know quickly of the paint comes with the film. . i know it was a cpo car but bodywork can be hidden from audi & carfax by paying cash for repairs. . . be brave. . good luck most of my clients treat clear bra like a periodically replaced upgrade paint should be easily corrected if stained