modern milling can be a deterrent to counterfeiting, an aid to the blind to distinguish different denominations, or purely decorative. Sweating In the process of sweating, coins were placed in a bag and shaken. The bits of metal that had worn off the coins were recovered from the bottom of the bag. Sweating tended to wear the coin in a more natural way than clipping, and so was harder to detect. Plugging If the coin was large, a hole could be punched out of the middle, and the face of the coin hammered to close up the hole. Or the coin could be sawed in half, and a plug of metal extracted from the interior. After filling the hole with a cheaper metal, the two halves would be welded back together again. Verbal references to plugged quarters and plugged dimes eventually yielded the common phrase "not worth a plugged nickel" (or 'plug nickel', or even a plugged cent), emphasizing the worthlessness of such a tampered coin. References Further reading External links Coins Commercial crimes