No need to polish shell ever, renovateur provides enough of a shine. Crema Alpina gives an even better shine if you can find it.Most of them do yes. Using the inside of an athletic sock you can buff out some really bad scratches if you use enough elbow grease. The buffing will mar the surface a bit though, to bring back the shine just apply renovateur. For the worst scratches I have some creme cordovan from Saphir...rarely necessary though.