You might try a scslpel blade to clean the binding. My RC4 A build had a major mishap in staining, and I'd also scratched the hell out of the binding so that black stain was all jammed in it. I used the edge of a very sharp scalpel to scrape across the surface of the binding as you would rolling butter on a knife. Rolled a thin layer of the plastic, taking the scratches and staining with it leaving the binding perfect.