*Maroon* scotchbrite.
Works well, I think first degreasing/cleaning the alum helps as well.
Steel wool ought to work just fine, too.
99c sell the green stuff in 6" stacks for, uh, 99c.
Also, if you are doing this in any quantity, you can get scotchbrite made
for belt sanders. For my 4x24, they were $10-12 *each*--goodgawd.....

This is one of my medium-sized "production runs" - aka two of them


Haven't tried it, but a sponge and Comet or its equivalent might work
nice--mebbe great.
Scotchbrite tends to get gummy from alum.

Face milling would not be a problem, as the pieces are short, and I don't
think you'd have to mill off more than .010, altho that might not get the
deeper dings/gouges.

It probably would not get all of them, but then neither would
scrotchbright. How would the scotchbright finish handle fingerprints?
The parts in question form the outer casing of the offending gizmo and
are likely to handled far more than the largely flycut and visible innards.

Bill