Green’s Dictionary of Slang

(a) (UK student) to initiate new students by a variety of rituals, esp. making them drink salt water or swallow dry salt; thus salting n.

1570		Lamb. Ms. in British Mag. (1847) XXXII 366: My lord edward zou[ch]..hys matriculation ijs...hys saltyng iiijs .
[1636		Martin Life of First Lord Shaftesbury i, 42: On a particular day, the senior undergraduates in the evening called the freshmen to the fire, and made them hold out their chins; whilst one of the seniors with the nail of his thumb (which was left long for that purpose) grated off all the skin from the lip to the chin, and then obliged him to drink a beer glass of water and salt [F&H]].
a.1644		T. Twyne Twyne Ms. 753: The saltinge of fresh men which hath beene antiently and is yet at Oxford vsed at their first comminge, was perhaps borrowed or continued from this custome at Athens [OED].

(b) (UK prison) to initiate a new prisoner.

1958

(con. 1940s) B. Behan Borstal Boy 122: Stories of the way new receptions were ‘salted’, with their shorts taken down and all manner of stuff rubbed on or poured over them.

(a) (US) to shoot (dead).

1840		W.G. Simms Border Beagles (1855) 258: This agent of his excellency [...] once fairly salted, [...] we shall have no trouble for some time to come.
1907		C.E. Mulford Bar-20 xi: Th’ feller yu’ salted yesterday was a bosom friend of th’ marshal’s.

(b) to ignore, to not bother.

1899–1900

C.L. Cullen Tales of the Ex-Tanks 173: I offered him a thousand of my roll. ‘Salt that,’ said he. ‘I don’t need it.’.

(a) to increase (e.g. a cab-fare).

1840

London Mag. Feb. 11/2: [T]hen, in a stage- whisper, perceiving that he had caught a ‘flat,’ [...] ‘But never moind, I'll “salt” his fare on the rum’un!’.

(b) to ‘improve’ the apparent quality of a mine by planting specimens of the ore it supposedly yields.

1853		C.R. Read What I Heard, Saw, and Did 32: ‘Why was he so anxious to sell it?’ ‘Because,’ answered his neighbour, ‘he had salted it himself, and then taken his friends to look at it.’.
c.1856		P. Shaw Ramblings in Calif. 62: One of the most successful tricks heretofore in vogue among the mining speculators, was happily denominated salting.
1866		Columbia Citizen 11 Aug. 3/2: We must devise some means of making the claim appear rich to some prosperous greenhorn [...] I’ve got it! We’ll salt it! [DA].
1872		‘Mark Twain’ Roughing It 311: One plan of acquiring sudden wealth was to ‘salt’ a wild cat claim and sell out while the excitement was up.
1880		Bulletin (Sydney) 30 Oct. 2/3: In the Hurdsfield ‘salting’ case, tried at Ballarat last week, the jury could not agree.
1885		Daily Tel. 22 Sept. n.p.: One of the first to practise the art of salting sham goldfields [F&H].
1894		Pall Mall Gazette 22 Dec. n.p.: [Title] The art of salting a mine .
1895		Truth (Sydney) 17 Mar. 16: After which, he sells out his shares in a ‘salted’ mine and fairly haunts the Exchange.
1900		Ade More Fables in Sl. (1960) 148: While he was Salting the Mine [...] a few Natives came along, and were Interested.
1902		‘Dads Wayback’ in Sun. Times (Sydney) 16 Nov. 5/5: ‘But there’s er lot o’ coves as ain’t up ter cornerin’ ther market, or sellin’ wild cats, or saltin’ claims’.
1907		Lone Hand May ‘A chap told me tonight there were rumours of salting. I explained to him that it was our mine and I think he aw daylight’: .
1918		C.J. Dennis ‘Hopeful Hawkins’ in Backblock Ballads 30: The confounded mine’s a duffer; for that simple-minded buffer / He had salted it.
1926		J. Doone Timely Tips For New Australians 23: to ‘salt’ a mine—To lay a little gold in a mine where it will be found and so advance the sale of shares.
1945		Baker Aus. Lang. 96: To salt a claim (1853) described the practice of ‘doping’ or faking a worn-out or useless claim with gold dust to make it appear productive.
1950		Goldin et al. DAUL 184/1: Salt. To set as bait; to place ores or minerals in a mine, oil in a well, or to do any similar act, in order to deceive a prospective buyer or investor; to swindle by baiting, as by placing genuine currency in a ‘money-printing’ machine.
1954		Wodehouse Jeeves and the Feudal Spirit 71: Haven’t you ever heard of salting mines? It’s a recognised business precaution. When you’ve got a dud mine you want to sell to a mug, you sprinkle an ounce or two of gold over it and summon the mug to come along.
1978		A. Brink Rumours of Rain 106: It involved a Cabinet Minister’s son, accused of ‘salting’ a newly opened mine in South-West Africa.

(c) in ext. or fig. use.

1911		E.S. Sorenson Christmas in the Bush in Life in the Aus. Backblocks 291: On the goldfields the miners take delight in surreptitiously introducing a few small nuggets into the plum-duff [...]. This habit of salting the pudding induces a good deal of prospecting.
1950		see sense 3a.
1979		G. Wolff Duke of Deception (1990) 207: When we passed the boater for tips we salted it with a fiver.
1987		C. Hiaasen Double Whammy (1990) 210: He had also planned to salt the lakes with a dozen big Florida hawgs.