Green’s Dictionary of Slang

1. (UK Und.) money, esp. as taken from a victim by cut-purses or pickpockets.

1592		Greene Blacke Bookes Messenger 20: I [...] spied a good bung containing many shels as I gest.
1608		Dekker Belman of London (3rd) H1: The purse is the Bung. The money the Shelles.
1611		Middleton & Dekker Roaring Girle V i: 1st cut: Shall we venture to shuffle in amongst yon heap of gallants, and strike? 2nd cut: ’Tis a question whether there be any silver shells amongst them, for all their satin outsides.
[1901		‘Hugh McHugh’ Down the Line 17: ‘Did you bet?’ inquired Clara jane. ‘Only $730,’ I said; ‘A mere bag of shells’].
1997		N. Barlay Curvy Lovebox 53: We have a smoke to celebrate the shells we pulled in.
2000		N. Barlay Crumple Zone 76: He’s been a bit silly. He go’a come froo wiv some serious shells. Like by last week.

2. (US und.) constr. with the, the game of thimble-rig n. (1)

1896		F. Hutcheson Barkeep Stories 60: ‘[W]e snake de main bull o’ de town an’ start t’ play de shells’.
1905		F. Hutchison Philosophy of Johnny the Gent 37: Why, the shells are as old as Casey’s whiskers, ain’t they? Everybody ought to be wise to ’em by this time.
1912		H.G. van Campen ‘Our Theatrical Boarding House’ in L.A. Herald 26 Nov. 6/5: ‘l remember when I first met you, Louisa, our pa was sellin’ cough syrup from a buggy an’ dealin’ the shells in between’.