From what you say i think your only option is to wetsand. If it's rough start with a 1000 grit and slowly work up to 2000 grit. If your careful trying not to burn through the paint you should be able to get all the clear off the fenders. If you just do the damaged area you'll see the difference with whats cleared and whats not. Just wetsand all the clear off and use a good 3M compound and buff it out and i think you'll be okay. Its called 3m perfect something? Its a 65 bucks a bottle but works perfect. 2 different finish types, get both! Don't try the cheap compound in the auto stores. I did and had to respray half my car

The cheap shit won't get the scratches out! I've been working on wetsanding my car for almost a month now and its really slow going. Just take your time and don't go through the paint (stop once your wetsanding water color changes to your paint color, clear coat comes out kinda yellowish). Good luck!
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1980 luv sport 4x4 Just a memory now
Frame rusted from the inside. Truck stripped and now looking for a new donor in southern ohio