Chevylee and Slimsilvy- the covers were really pretty easy, get a dremel or high speed air tool with stipping and buffing pads and go to town. the casting is a little rough so you'll wn't some pretty abrasive stripping pads, then just go to a smoother finish untill you don't see any more scuff marks. after that you can either polish them or brush them. polishing will take a little more time, but once the metal is smooth you can polish it just like wheels. To brush the aluminum just get a scotch pad and make sure everything is in the same direction. Its a huge pain to brush the timing cover.
It took me quite a bit of time since this was my first time doing it. But if you have ever finished wood or fiberglass its pretty much the same idea. start rough, and slowly work to finer grits/pads untill you have the finish you want. I'm clearing mine to keep the finish on them. hopefully I will have a pic of the engine assembled in the next few days, just waiting on parts to get here.
EDIT: I would recommend using the valley cover as practice like I did, its the easiest one to do and is the easiest to just paint over/ cover up if you mess it up.