Stains in the blade canbe removed with very fine sandpaper, I would suggest hand rubbing the blade with 600 grit paper and Windex for lubrication. The trick is to keep all scratches going the same direction and carry them all the way to the tip...looks more professional that way then oil the blade to prevent streaks reoccurring.
Dents must be removed before polishing the blade. A good way to do this is to glue a piece of cloth backed 240 grit sandpaper to a hard FLAT surface then stroke the edge along that surface until the dents are gone.
A knife can be resharpened any number of times as long as care is taken not to change the angle of the edge. Re establishing the edge bevel from incorrect sharpening is best done by a qualified knifemaker, it takes time and skill. I would suggest you purchase a copy of Knives 2010 to get a list of knifemakers in your area.
Good luck with your project.