Currency with a poor exchange rate

CNN reports on the NEJM "medical mystery" X-ray contest I participated in:
The 62-year-old man came to the emergency room of Cholet General Hospital in western France in 2002. He had a history of major psychiatric illness, was suffering from stomach pain, and could not eat or move his bowels... Dr. Lindsey Baden, an editor at the journal, reported that 666 readers in 73 countries -- mostly doctors or doctors-in-training -- contacted the journal to try to solve the mystery. Almost 90 percent settled on diagnoses consistent with pica, but only 8 percent correctly identified coins. "

Yay, me, in the top 8 percent (of readers with time on their hands). Of course, I had preparation last October, with a psych/surge patient who swallowed needles. Still, I was surprised by the sheer value of the coinage in the NEJM case: US$350, or twelve 'pounds' worth. This is one of the few occasions where "pay as you go" works well for doctors and patients.