If the scratches on the clear bra are very light you can sometimes just use a heat gun and extreme caution in a controlled environment with no wind.
Run the gun over the bra with proper lighting and you will gradually increase the heat concentration until you see the surface smooth out. Sometimes just a sunny hot day will do the trick if you have a dark color paint.
You can't really polish it, it's too soft and will either burn or just look even worse.
My suggestion would be to just not worry about it and change out the front every 3-4 years
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