Edelbrock calls their shiny finish "endurashine", and the internet says it's a metalized finish with a clear powdercoat on top. Makes sense, since I've seen it flake before when in super corrosive settings.
Pretty much any mechanical cleaning will probably damage it. Dry ice blast probably wouldn't, but it will remove the areas where it's already compromised.
Vapor blast or vapor home works really well. High speed tumbling can do wonders, but with a carb I'd be worried about packing orifices with media. Plus, it takes pretty fine stones or media to get all the sharp inside geometry of a carb, and a few seconds too many in a high speed tumbler will make expensive scrap.
Most carbs aren't straight aluminum, but a die casting alloy that may also contain zinc and magnesium. It's often a highly reactive metal that will oxidize rapidly and polishes poorly. Some sort of chemical barrier is needed to make an inert surface. I'd go with shops that specialize in carburetor restoration and refinishing. But there's nothing wrong with starting with a blast job. With care, it won't degrade too fast, but won't last if near salt water or exposed to varying humidity.
