There's a 1924 Papa Charlie Jackson version on Spotify. The version I know is Mississippi John Hurt, though I have heard folk do their own versions live too. Wikipedia quotes Jan Obrecht's book on Jackson as a source for the idea that versions circulated in New Orleans prior to the release of Jackson's '24 version.

Both Hurt's version and Jackson's one both have a tinge of ragtime. Jackson is good on the banjo. I think this chord sequence crops up quite a bit in early guitar ragtime?

Penguin Dictionary of Historical slang gives one meaning of 'salt' as copulate for the verb and also shows its use as a noun, related meaning.
It doesn't list a related historical use as an adjective, but the link seems obvious.