Washington ? Treasury Secretary John Snow is the nation’s top money man, but he might need a refresher course on the greenbacks the United States makes these days.

Snow was asked during an online “chat” Wednesday what form of currency he would like to have his image on.

“I would put it on the $500 bill,” Snow replied. “It has the least circulation. That way I wouldn’t have to see myself too often.”

Oops.

The United States stopped printing new $500 bills in 1945 and stopped issuing them altogether — along with $1,000, $5,000 and $10,000 notes — in 1969, due to lack of use, says the Treasury Department’s Bureau of Engraving and Printing.

Since 1969, the $100 bill has been the largest denomination note cranked out by the bureau and in circulation.

The image of William McKinley, the 25th president, appears on the front of the $500 bills, which along with the other higher, discontinued denominations are more likely to be turn up in the hands of collectors than in cash registers.

Even if the $500 bill were brought back, Snow’s image couldn’t be put on it, at least not right now. Living people’s visages cannot appear on U.S. currency.

Afterward, Treasury spokesman Rob Nichols said that Snow was joking when he made the comments during an interactive exchange posted on the White House Web site.