When I worked at building displays for Aurora plastics (many, many years ago) we used a very mild polishing compound - meant for automotive use - called Liquid Ebony. It was not nearly as viscous as the typical liquid polishing compound and you could barely notice that it was abrasive. Since then I've seen similar products at automotive painting suppliers although I can't remember the names off hand. Anyway, these products are very mild, meant to be used on the final polishing step of custom paint jobs. I'm sure that if you go to an automotive paint supplier and describe this, you can find a similar product. For a small section of a bicycle (or a plastic model, for that matter) you apply it with a cottton ball. Best regards, Fred Rednor - Arlington, Virginia