Green’s Dictionary of Slang

(US Und.) a variety of fraudulent financial paper: e.g. bad cheques, counterfeit money; .

1929		D. Hammett Dain Curse 217: We wanted him for spreading reams of orphan paper through the Northwest [. . . .] ‘He never thought enough of me to risk passing any bum checks so I could have things,’ she complained.
2000		(con. 1940s–60s) Décharné Straight from the Fridge Dad 139: Orphan paper Rubber cheques, funny money, counterfeit currency.