Before the 1660s all English coin was produced by hand; contemporaries called it “hammered” money. It wasn’t uncommon for “clippers” to scrape away small amounts of precious metal from the edges, pass the coin back into circulation, and pocket the illicit proceeds. In 1662, in a bid to halt clipping, the Mint introduced mechanized production; “milled” coins bore a serrated edge that made it easy to detect when a coin had been clipped. But many older hammered silver coins remained in circulation, and upon these clippers went on plying their trade. Hammered coins naturally shrank over time, but so gradually that they continued circulating at normal face values. Clipping quickened with the onset of the N…
Kleer, Richard. "The 1696 Recoinage". The Literary Encyclopedia. First published 14 October 2003; last revised 30 November -1.
[http://www.litencyc.com/php/stopics.php?rec=true&UID=1304, accessed 20 April 2015.]