Spin reel? Or fly reel?

Tom

Yes ... what's the reel model?

I believe there were enough of the Ambidex No. 1 model made (just like this into the 60s) that, short of a mint, boxed reel, it has modest collector's value (at least within any of our lifetimes).
They do work well, and I know at least one person on the forum who regularly fishes these.

So its greatest value is how you value it personally.
If you can spot paint it and save the markings, that might make a cool reel.
I don't think solid paint over the markings would look too cool, but it's also your reel.

I also think its cool to fish an aged reel that shows its mileage and keeps fishing.

very nice, I see the shields came off

I first soaked the reel in a light vinegar solution for about 1 1/2 hours then removed the paint with steel wool, and a razor blade, I also had to use a wire brush in a few spots. The paint came off really easy. I was even able to take a lot of it off with my fingernails.

I got the shields off, by removing as many of the pins as I could from inside the reel with a punch. There were about 2 or 3 pins I couldn't remove from the inside, so I slipped a credit card underneath, then pried them out with a couple putty knifes. The pins are very small, and come out easily. You could see them below.


I reassembled the reel , just to make sure I don't loose any parts, or forget how to put it back together before I paint it. (I did not re-install the pins yet, I will be able to reuse them though, I just did not want to put them back in just yet) I think the reel would also look pretty neat if it was just polished (which I haven't done), I'm still planing to re-paint it. The paint on the spool was in good shape, so that was left alone.

any time you're getting into shop chemicals, you've crossed the line from science to art.
Any time you're talking about painting aluminum, and mixing it with water, there is no science, anyway - science tells you it can't be done, which is why it's been replaced with anodizing.

aluminum passivates in mild acid, is actively attacked (corroded, etched) by alkalis and strong acids.
If it was an acid, what you may have actually been doing was passivating the aluminum rather than etching it - kind of like the old "lead" finish on prewar alloy reels (which is acid bronzing with mixed acids and arsenic salts). I believe Young continued some variation of this process on their postwar reels, and you can see the bronzed layer beneath their paint

The mixed acids I know that etch aluminum include hydrofluoric, and you don't want to mess with that.
Brass and bronze is going to passivate in all but the strongest alkali, will crack in ammonia, and will dealloy and plate copper onto your aluminum in any acid stronger than vinegar.

if you know something that worked for you before, it might be worth a try - drop a penny and a nail in it and see how the two behave.
If the nail turns copper, the bronze will probably defeat the etch you're trying to get on the aluminum.