I had good luck removing dried white paint from the inner fender well where the previous owner had run through some paint. I tried many things , but the only thing that I had on hand, that would dissolve the paint was some printers blanket wash. What's that? A non oily kerosene/mineral spirits/Naptha mixture is the best way I can describe it. It worked on the painted rocker panel as well. GooGone or GoofOff as previously suggested, will probably work as well.