After looking at my emblem, it appears to have a suitable plastic coating on it. You could try and polish yours out. Depending on the depth of the scratch will depend on the amount of effort on your part it will take. If you have minor scratches, scuffs, etc. you can use Novus Plastic Polish on it and it should remove these, the amount of effort invloved will depend on the scratches. If they are deep scratches you may actually be able to sand these out using various grades of sandpaper, with final sandpaper being at least a 2000 grit followed by polihing with Novus. For those of you that have never heard of or used Novus look here.
novuspolish
I orginially heard about this product from some model building websites as to how to polish out a paint job on a model car, and it works as well as everyone said it would for that. It also works amazingly well at cleaning your headlights as well. I rrecently redid mine and while not perfect they look 100% better than they did. I have found most Harley dealers sell this. I got an 8oz. bottle for like 7 bucks and I've only used about half of it. It's a worthwhile product to try.