Brushing aluminium enclosures... How do I get rid of these blemishes?

[Aentons]

What are these splashes/stains artifacts and how can I get rid of them?

[Aentons]

More pics

[Aentons]

This is my first time doing any kind of metal brushing so not sure what I'm doing wrong.

This is an official Hammond 1590DD. I started out with hand sanding with 220 grit wet paper and went up to 400 and and that didn't do it. I have hit it with down to 80grit wet paper and worked my way up to 2500 and tried to polish it away with a polishing wheel on a drill and it was a no go. I hit with a circular wire brush on a drill and it's still there. 80/220/400 abrasive buffs an a drill. Dremel 180/280/400 abrasive buffs... Still there

What is it?

[EBK]

Cast aluminum will always have subtle splotches that result from how the metal flows into the die and any variations within the alloy itself (impurities, etc.).  You can get purer surface appearances from machined enclosures, I believe.

[Aentons]

Cast aluminum will always have subtle splotches that result from how the metal flows into the die and any variations within the alloy itself (impurities, etc.).  You can get purer surface appearances from machined enclosures, I believe.

Other than paint it... Is there a good way to minimize it?

[EBK]

I'd say embrace it.  It gives the metal some extra character. The pattern likely exists through the entire thickness of the metal, so no amount of sanding or brushing will change it much.

[Aentons]

Yep, that's prob for the best.

Just curious tho... any idea if it would show thru if was anodized?

[EBK]

Anodizing would probably make it worse.

If you are interested, here is an above-my-brain-level description of these types of blemishes (at least, I think they are talking about the same thing):
https://www.giessereilexikon.com/en/foundry-lexicon/Encyclopedia/show/hard-spots-3860/?cHash=9ecee71d0bc564a5f0dac6ae8396e8b6

[mjg]

Keep in mind that once you start using the pedal, you'll have your fingerprint marks smeared all over it too.  You might find that you don't notice the original marks so much then.