Green’s Dictionary of Slang

1. one who gathers the scraps from the floors of a meat-market.

1861

(con. 1840s–50s) H. Mayhew London Labour and London Poor I 255/2: Lads and young men, known there as ‘finders.’ They carry bags round their necks, and pick up bones, or offal, or pieces of string, or bits of papers, ot ‘anything, sir, please, that a poor lad, that has neither father nor mother, and is werry hungry, can make a ha’penny by to get him a bit of bread, please, sir’. This is often but a cover for stealing pieces of meat.

2. a thief.

1860		Hotten Dict. of Modern Sl. etc. (2nd edn) 140: finder, one who finds bacon and meat at the market before they are lost, i.e., steals them.
1873		Sl. Dict.

3. (US Und.) that member of a safe-blowing team who actually blows the safe.

1926

‘Und. and Its Vernacular’ in Clues mag. 158—62: finder Member of a safe-blowing gang who blows the safe.