The main thing I do when I put tape on is put it in the place that is least likely to mess up the airflow which would change the lift. You could try sanding the blades also, but it might be hard to get back to that nice polished look that CF blades have, and you would probably need to seal where you sanded with some sort of something, like what holds the CF together. CA or some sort of epoxy would probably work (maybe someone else has more info on that)