Green’s Dictionary of Slang

(UK Und.) the clippings from doctored gold coins.

c.1698		B.E. Dict. Canting Crew n.p.: nig c. the Clippings of Money.
1709		N. Ward Compleat and Humorous Account of Remarkable Clubs (1756) 294: Here the Gentlemen of the Nig, in their Cant, but vulgarly called Clippers.
1719		A. Smith Lives of Most Notorious Highway-men, etc. (1926) II [as cit. c.1698].
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
a.1790		H.T. Potter New Dict. Cant (1795).
1809		G. Andrewes Dict. Sl. and Cant.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1835		G. Kent Modern Flash Dict.
1848		Flash Dict. in Sinks of London Laid Open.