The Hercules is black, so not much in the way of color matching/change is happening. The polish just shines up the paint. I also hit the chrome fork cap with Simichrome, which is another favorite of mine.
The method for both is basic: wipe on a generous amount of polish, burnish with a soft cloth, check your work, and then repeat it all. I finish by using a clean cloth and wiping it down until it shines well enough. There was some house paint on the chrome fork cap. I removed that with acetone before I polished the cap with Simichrome.