Employees at Sherman Elementary School had noticed marks on the couple's four children and police took the children away April 30. The marks had been produced by a traditional Asian healing technique commonly called coining, Seng Chan and Kaying Lor said. The technique involves rubbing ointment into the skin with a coin or a spoon.
—"Second family cleared in coining case," The Associated Press, May 14, 2002

The little Cambodian girl shyly lifted her T-shirt and Trish Bathard was briefly horrified. Radiating from the eight-year-old's spine were angry red lines, seven or eight on each side, like branches of an incongruous, stylised Christmas tree.

Had Mrs Bathard not known Kunthea and her family, had she not been her English teacher and mentor at Miramar Central school, she would have thought the girl had been subjected to some awful form of abuse. Instead Kunthea was showing the results of the traditional Southeast Asian health practice of coining.

It looks alarming. Just recently a relieving teacher taking swimming at an Eastern Suburbs school panicked at the sight of a child's striped back.

In fact, coining — or goh kyol (rubbing the wind) — is relatively painless and afterward even pleasurable. Adults and children alike are coined, though not babies, as their skin is too delicate.
—Val Aldridge, "How money can heal," The Dominion (Wellington, New Zealand), March 19, 2002

A better familiarity with folk remedies also might avoid misunderstandings: A common Vietnamese practice of "coining" — the forceful rubbing of the neck, temple or other body parts with a coin to the point of bruising — has led some U.S. teachers to mistakenly think a child has been beaten.
—Karlyn Barker, "Bad Circulation? Try Some Sliced Deer Antlers," The Washington Post, November 6, 1988