Green’s Dictionary of Slang

(US) to discount a promissory note at a very high rate of interest.

1807		Irving & Paulding Salmagundi (1860) 242: Those who shave notes of hand [...] are the most respectable, because, in the course of a year, they make more money.
1834		A. Greene Perils of Pearl Street 123: To sell [notes] at a great loss to the brokers, or, in other words, to get them unmercifully shaved.
c.1870		Life in N.Y. in Bartlett Dict. Americanisms n.p.: Make your money by shaving notes or stock-jobbing, and every door is thrown open [...] [F&H].
1896		Harold Frederic Damnation of Theron Ware 40: People tacitly inferred that he ‘shaved notes’ [DA].
1903		A.H. Lewis Boss 182: I’m as much entitled to get action on it in favor of myself as a bank has to shave a note.