Green’s Dictionary of Slang

sausage (and mash) v.

to cash (a cheque).

2001

J. Burkardt ‘Rhyming Sl.’ Wordplay 🌐 sausage and mash cash.

In phrases

sausage a goose’s (v.) (also sausage and mash a goose’s neck) [goose’s neck n.² ]

to cash a cheque.

1937		J. Curtis You’re in the Racket, Too 263: ‘You’ll have to sausage me a goose’s.’ ‘Sausage you a goose’s? What the hell are you talking about?’ [...] ‘Cash me a cheque, dopey.’.
1969		S.T. Kendall Up the Frog 11: Will yer sausage and mash a goose’s neck for me?