I had the same problem with degreaser getting on my paint near the rear of the hood, which is probably much worse than your vinylex.
You'll need some good wax, maybe the turtle wax scratch remover. Wax the spots with that.
If that doesn't work, a small amount of rubbing compound will definitely remove the residue from the paint (if it bonded to the paint or clear coat), then you can rewax those areas to get them back to the shine of the rest of the tail. Good luck.
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Kurt B
'84 Carrera Cab.
carrera_cabriolet@yahoo.com