carpet, n.³ — Green’s Dictionary of Slang

carpet n.³

[ety. unknown]

(Aus.) £1.

1899		Bulletin (Sydney) 14 Jan. q. in Baker Aus. Lang. (1945) 110: [note] Flimsy, rag, carpet, £1 note.
1945		Baker Aus. Lang.
1955		N. Pulliam I Travelled a Lonely Land (1957) 231/2: carpet (cracker, frog, frogskin) a one-pound note.