I use a buffing wheel on an angle grinder for things like fork tubes and on a dremel for the perches. I sand down to about 800 grit and then use the wheels. I start with a black or brown compound and then white diamond. You can go finer than WD, but I do not find there is really any benefit. Gords aluminium polish is the best to finish and do upkeep but it is a little pricey.
Here is some stuff I did...
You can see I started this crank case cover, but it give you the idea of what I started with:
After:
Here are some forks, one done.. one not:
This is the adapter I use on the angle grinder
http://www.caswellplating.com/buffing-p ... shaft.html
You can get all the supplies at caswell and the products are really very good.