President Obama spoke at the White House today to officially nominate his chief of staff, Jack Lew, to succeed Timothy Geithner as Treasury Secretary.

In recent days, many have poked fun at Lew's loopy and rather illegible signature and referenced the possibility that it would soon be on U.S. dollars. Lew mentioned it in his remarks, noting that he and Geithner "share a common challenge with penmanship."

The president didn't let Lew off the hook either, ribbing him about it at the end of the event and telling him to work on it before his signature starts going on dollars.

"I had never noticed Jack's signature. And when this was highlighted yesterday in the press, I considered rescinding my offer to appoint him. Jack assures me that he is going to work to make at least one letter legible in order not to debase our currency, should he be confirmed," Obama joked to laughter from the press corps.

Watch the remarks: