I've done a couple of Salsa Shaft seatposts. My neighbor has a sandblaster at this store and he strips them for $10 cash. That's the hardest part and I just can't do the chemical approach.
I then use some 3M 1500 and 2000 grit wet/dry sandpaper to smooth off the surface, by hand. Finished with a rag and Mothers and/or Blue Magic. BM shines a little better and lasts longer. I have found that that finishes can vary from brands of posts. The Salsa was very micro-dimpled(from the bead blasted anodising I suppose) and to attempt to make that smooth would risk removing too much if I used a heavier grit to do so. A mirror finish like a vintage Campy Super Record isn't going to happen, but they still look good enough for me. If I do a crankset I'd get some polishing ball for the curved recesses.
On a more simple note, DT shifters are easy, and vintage Specialized hubs are too, at least the middle portion is. I don't try to do the sides or spoke holes, on the bike at least. I could do them off but that's a bit much, I just want so shine while I ride, and that's the middle, visible portion. :)