Shinplaster

Webster's 1913 dictionary calls it a joking American term for bank notes that had lost much of their value and for paper money under a dollar. Such small notes appeared when coins were scarce, issued by banks, stores and others, and they circulated widely between 1837 and 1861.

The name was a joke about their worth: a shin plaster was a cheap paper dressing put on sore legs, and the slang sense for devalued paper money is recorded by 1817. A sum paid in shinplasters was likely worth less than its face value.