Green’s Dictionary of Slang

(US) gold coin, usu. in pl.; thus mint drops, money.

1834		Eve. Post (NY) 6 Sept. 2/5: The quarter eagles are issued from the Mint [...] The Bank men are blank men, whenever they get a glance at these Benton’s mint drops.
1835		D. Crockett Col. Crockett’s Tour to North and Down East 119: But ‘the Bentons’ are all gone.
1840		Wkly Raleigh Register (NC) 21 Feb. 1/6: American mechanics will never sell their votes / For Mint drops or Treasury bills.
1840		Wkly Raleigh Register (NC) 21 Feb. 1/6: The brave sons of the South, John, will never own you more, / And Benton’s Mint Drops will not save — you’re rotten to the core.
1857		S.F. Call 26 Mar. n.p.: [He] Went to fight the furious tiger, / Went to fight the beast at faro, / And was cleaned out so completely / That he lost his every mopus, / Every single speck of pewter, / Every solitary shiner, / Every brad and every dollar [...] All the brass and all the needful, / All the spondulix and buttons, / All the rocks and all the mint-drops.
1862		N.Y. Times 24 Feb. 8/3: He poured out the contents of a small purse [...] $100 in ‘Benton mint drops,’ — shining yellow boys — eagles, double eagles [etc].
1872		Schele De Vere Americanisms 291: When the Hon. T. H. Benton [...] put his whole strength forward [...] to introduce a gold currency, he accidentally called the latter mint-drops, with a slight attempt at a pun. [...] For many years gold coins were largely known as Benton’s mint-drops.
1873		Wkly Oregon Statesman (Salem, OR) 7 Jan. 2/4: You were so much afraid that some farmer might pass, with a quarter or two of Tom Benton’s mint drops in his pocket, and tnbat you would lose the cent of it.
1882		Valley Falls New Era KS) 20 May 1/5: The treasury is the next group represented by mammon [...] with a large bag held open pouring in the ‘Tom Benton’s mint drops’.
1887		Reading Times (PA) 6 Jan. 2/2: Our pennsylvania farmers could then again wrap up their five-dollar pieces [...] and get some special small purse for the golden Benton mint drops.