Green’s Dictionary of Slang

(US) worthless paper money such as counterfeit notes; also in v. use [it has no monetary use].

1931		(con. 1918) E.W. Springs Rise and Fall of Carol Banks 54: What about that big wad of pretty wallpaper I saw you flash?
1949		Monteleone Criminal Sl. (rev. edn).
1960, 1975		Wentworth & Flexner DAS.
1972		B. Rodgers Queens’ Vernacular 138: wallpaper (fr underworld sl paperhanger = one who passes bad currency) counterfeit money.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 200/2: wallpaper v. to pass false cheques.