I posted this in the Dyna forum, but thought might get good responses here as well.

I've just purchased a used, 06 basic Superglide. It is a very clean ride, but has a place on the outer primary which looks like a chemical dripped and left a spot the size of a pencil eraser. Anyone had any luck with a way to successfully touch-up the silver powdercoat?

 

Try a dampened Mr. Clean Magic Eraser (the plain, original one). It helps keep my bike's powdercoat clean. Good luck.