Green’s Dictionary of Slang

(US) money.

1841		N. Carolina Standard (Raleigh, NC) 23 June 4/1: Billy Barlow — A New Rag — Currency Song. We’ll have rags and rag money, and Billy Barlow! [...] So hurra! for the ‘shinnies’ of Billy Barlow.
1879		Cincinnati Enquirer 7 Sept. 10/7: Wealth, Ore, Dust, Rocks, Spondulicks, Shekels, Ducats, Nicks, Flimsies, Filthy Lucre, Trash, Shiners, Shinnies--are the synonyms of money.