Green’s Dictionary of Slang

(UK Und.) stolen goods, esp. the booty gained by those who pick locks.

1514		Skelton Agenst Garnesche iii line 178: Soche pelfry thou hast pachchyd [...] Soche pollyng pajaunttis ye pley.
1591		Greene Second Part of Conny-Catching in Grosart (1881–3) X 86: In Lifting Law. The Pickelocke is called a Charme. He that watcheth, a Stond. Their engins, Wrefters. Picking the lock, Farsing. The gaines gotten, Pelfrey.
1608		Dekker Belman of London F4: The gaines gotten is Pelfrey.