What about wet sanding? Might be worth a shot?

So is the black layer paint or black Nickle? I'm not aware of any engraved drums that were painted. Engraved drums were either in Brass, Black Nickle, Chrome or Silver Nickle. My guess is that it was originally polished brass and someone painted it black at some point. Later someone brushed that silver paint on.

You can remove single layers of paint with Easy Off oven cleaner.

Since you have already removed a big section of the black at this point there is no saving it. I would find a strong paint remover and strip it all off and see what you have.

That makes perfect sense of course, the drum could originally have been nickel plated. But how did someone manage to strip the plating away? By sanding? There is definitely black paint underneath the silver and the white, it looks like the silver paint has dissolved that paint and soaked it up, and it comes off when using paint stripper. I cant imagine paint remover would remove nickel. I'll need to check this properly tomorrow, especially the inside of the shell. Here is a picture of the inside, and as you can see, the black colour is really smooth and covers both the bearing edges and the folds.

There was a black nickle engraved snare called the Elite but it had brass finished hardware. There was also an engraved Gold Elite version that was polished and lacquered brass finish but it also had brass finish hardware. Yours appears to be nickle plated which doesn't mate with a polished brass shell.

Thank you for sharing knowledge! I've been trying to figure out what it originally could have looked like, but the internet gave few answers really. As you say, the typical black engraved models came with brass hardware. On vintagedrumguide.com I found this pic of a black engraved snare that looks much like mine. Also, a company called "A Drummer's Tradition" has something they call a Leedy Black Lacquer; that one isn't engraved though. That drum is shown here: [ame="https://www.youtube.com/watch?v=ewsyEKdKYN0"]Late 1920's Leedy Snare Drum 5x14 Black Lacquer - RB's Pick!! - YouTube[/ame]

There were also non cataloged models made by all of the drum companies so that could easily explain it. It seems odd that they would have painted an engraved shell from the factory but anything is possible I suppose.

There was a white enamel, black enamel and a gold enamel finish offered, but all were un-engraved.

threeonthefloor.com has a bunch of examples of 20s Leedy snares. It appears that even the polished brass "gold elite" was painted black on the inside.

http://www.threeonthefloor.com/1920s-leedy-gold-elite-model-snare-drum-5-x-14/

As it turns out, the shell was not painted but nickel plated on both sides, just as "thin shell" suggested. I stripped (almost all of) the paint off, and underneath it was what remains of the original plating. Not a lot left! The plating was unaffected by the paint stripper, as expected. So, someone has removed the plating by sanding, possibly long before I was born. Still, the shell seems to be in very good condition, and now I need to figure out what to do with it. I could paint it, or maybe leave it as it is.

Interestingly, the plating on the inside looks satin, whereas the remaining plating on the outside, especially in the grooves, is still glossy.