From Old French
pelfre, goods, especially such as are taken by force,
plunder.
Hensleigh Wedgwood's Dictoinary of English Etymoogy, 1878
Rubbish; whence pelf, the philosophic term for money, often applied by cynics, who by no means think money the rubbish they assert. The metaphorical use of the word has entirely superseded the original. Ill-gotten gains are called pelfry
Charles Mackay's Lost Beauties of the English Language, 1894