Currency Defacement

I was wondering if somebody could point me to the law that deals with the defacement of currency? And perhaps also, a link to a government website that outlines exactly what constitutes defacement. I need to "educate" a teller at a local bank (sigh)

http://codes.lp.findlaw.com/uscode/18/I/17/333

The important part is "unfit to be reissued". If you stamp only in the white area of a bill or the border, and not into the security areas (seal etc) then the bill is for sure ready to be reissued. My style of stamping still works with ATM, and any convenience machine accepting $1 bills.

Our intent is to see where they go and get TrackPoints, for sure our intent is not to make the bill unfit to be reissued, we would never see hits.

Here the law:

18 U.S.C. § 333 : US Code - Section 333: Mutilation of national bank obligations

Whoever mutilates, cuts, defaces, disfigures, or perforates, or
unites or cements together, or does any other thing to any bank
bill, draft, note, or other evidence of debt issued by any national
banking association, or Federal Reserve bank, or the Federal
Reserve System, with intent to render such bank bill, draft, note,
or other evidence of debt unfit to be reissued, shall be fined
under this title or imprisoned not more than six months, or both.