@ bigkahuna: As far as I know, the castings were dipped into "Type-III Hardcoat/Class I Natural" anodizing solution. (Exceedingly nice work on your majorly detailed restoration/documentation effort by the way... just got done reading thru ALL of it)
@matteroner: I will be scraping the inside of one of these castings to see how deep I have to go to get back to what looks like aluminum. If I proceed with a DIY polishing effort, that will hint at what grit to start at. I mean, I can polish agates, gems and minerals and alumunim is considerably softer than some of those I work with in my lapidary hobby, so this shouldn't be too difficult conceptually. I don't own a bench grinder though so I can't attach convenient polishing/sanding wheels to it. That might have to change.
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If I get these powdercoated, I hope there's a nice shiny silver (untextured) color available. I've been searching the awesome forums here at AZBilliards trying to find as many photos of powdercoated pockets as I can. Can't really use the GC copper pics to judge by. I don't know exactly what state my pockets are currently in... that is, they "appear" to be ready for some kind of coating because it looks like a smooth, flatter than flat gray color (slightly beige/olive too)... completely sheen free at present. I'm going to continue researching what "chrome/sandblast" looks like before deciding on powdercoating because i've been quoted $243.50 to do all 10 pieces that way (or $487 for chrome that might not turn out the way I hope.)