Its something I learned a few years back when I decided to restore a set of old torq-thrust wheels. Wasnt necessarily trying to, but found that I could achieve a nice satin finish to the aluminum and it translated well to the valve covers.
Light bead blast, 20-30 psi in a siphon cabinet. That will give you a nice, clean base to work from without harming the surface of the aluminum (i.e. pitting).
Then I work my way slowly back up. Grey scotch-brite followed with a fine steel wool will smooth it out pretty well. Then an application of Mother's mag polish by hand to even out the surface and give some sheen, but it wont be much. I finish with an aluminum/mag wheel sealer.
I cant guarantee it will work perfectly for you. Its something Ive been doing for several years, so I have gotten a feel for it.
The last set I did (the last two pics in the TC thread) were abused previously by someone who shouldnt have been trying to clean them up. They didnt respond as I expected, and were more work than usual. Took more time and varying methods that I have used in the past on other things to get them where I wanted them.
Give it a try if you want. You wont ruin them, and if you get frustrated and give up you can always send them to JM.