I would use around 400 grit sand paper on a sander to take out scratches etc. Use 600 wet, you can stop there or go higher, the finer you go the better it will come out. Get a buffing wheel from home depot I think they are like 40 bucks. Use the stiffer wheel with a good rouge and it should come out with mirror finish. Then use something to seal it I forgot the name starts with a Z.