doylee4692 (ANOTHER login name that has got to have some meaning behind it!)
Gotta ask what make, model, and year of motorcycle AND what color? Was it custom-painted?
Those questions stem from how old the paint might be and what type of paint (lacquer, single stage, clear-coated poly or clear-coat ceramic if it was custom-painted). The color may just be an eye-thing, meaning a white might show the stain more, while a dark may "hide" that stain, even after you`ve polished it out.
I would NOT recommend wet sanding it unless you have some experience doing so. NOT that it cannot be done, but the risk of not knowing how thick the paint is without some Paint Thickness Gauge to verify that value COULD lead to burn-through if one is not careful wet sanding in a willy-nilly (IE. inexperienced) way. I do not think your motorcycle is a good vehicle to "experiment" on, BUT you know your detailing and body shop abilities better than I do and how the motorcycle paint looks to you.