Glass beading the surface should brighten it up. You will need to spray some epoxy clear on to keep it that way.

Use soda blasting. It is for aluminum, etc effective but safe.
Here are pieces from my '31 Franklin that were soda blasted. All aluminum except exhaust and it will do that also !!

What some pieces looked like before soda blasting.

I attempted soda blasting a small area a few days ago after cleaning & degreasing the pump but it didn't really do much. If anything it looked a tad bit darker. Not having soda blasted before I wasn't sure if needed more blasting time or what, so I stopped before I messed it up any further.

Your results Richard are pretty astonishing, especially for as dirty as they were to start with. I've read that bead blasting works & is often what refurbishing of pumps get hit with before a sealing top coat of some sort. I do see remnants of anodizing in some areas on the pump, but I don't know what a factory finish is suppose to be &/or if it's worth chasing a specific finish too far. Not having an actual soda blaster, tumbler or media blaster I may have to take it somewhere if I cannot find a relatively inexpensive DIY solution for home.

Note that I didn't do the blasting--was a professional multi-media blaster. Cost of what you see was about $150 and extremely worth it. I had to drive about 40 miles to find someone that had it.

In the end, I couldn't find anywhere to bead blast the fuel pump. So I cleaned it up as best I could & rattle canned it with satin clear. Overall, looks pretty decent, all except for the dent in the air dome.