Don't dispair.
If all else fails, sand the stuff off and paint the plexiglass with automotive clear coat, sand and buff like you would a paint job. You don't even have to have the plexi sanded out when applying the paint. The fine scratches will fill perfectly. I did this with a craptastic plexiglass window in a Parish top. Leaves a clear finish that is as good as you are willing to work for. My only problem was internal fracturing in the plexiglass, which the paint could not help.
I think the paint is probably a more durable finish that the plexiglass.
Bill
If all else fails, sand the stuff off and paint the plexiglass with automotive clear coat, sand and buff like you would a paint job. You don't even have to have the plexi sanded out when applying the paint. The fine scratches will fill perfectly. I did this with a craptastic plexiglass window in a Parish top. Leaves a clear finish that is as good as you are willing to work for. My only problem was internal fracturing in the plexiglass, which the paint could not help.
I think the paint is probably a more durable finish that the plexiglass.
Bill