The 1970-S US quarter struck on a 1941 Canadian quarter is for sale on Mike Byers web page for $35,000.
https://mikebyers.com/1949701-013.html It's certified by NGC as PF-65.
The chances of finding another are close to impossible. It was part of a hoard of "Employee Assisted" errors from the San Francisco mint. Someone made some really strange combos of coins on coins, coins on tokens, etc. When they were found they sold for big bucks, but it's thought that no other coins like this exist.
This kind of error also draws the interest of the Secret Service, in that they may be subject to seizure as illegal to own, because they are "the fruits and instrumentalities of crime" and are the property of the government and should never have left the mint.
ANA ID: 3203813 - CONECA ID: N-5637 Clean a coin that may be worth collecting? Please DON'T! When in doubt, leave it dirty!!
