I'm not to familiar with the ceramic coating but I think an S.O.S. pad (steel wool with a detergant )should remove the spots. The ceramic coating should be hard enough to take it. I would guess the rust spots are just on the surface.
The best way to prevent them; don't drive in the rain or snow

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Good luck!
Brad R.
1992 L.X. 5.0 coupe
MODS: A few little bolt ons

New Best time ...11.60 @ 128 mph @ 2000+ ft altitude.
Rice Haters Club member #39
Users rides #2542