Detecting Paper money

[goldfinder]

The bigger new bills have a metal stripe. It should be possible to make a detector that would tune into the stripe. It has a specific length; hence, a resonance to that length. Since it is only a few inches long the frequency would be rather high, in the microwave band.
There are many millions of paper money stashed by drug dealers in case they get caught and need a money bootstrap when they get out of prison.
Goldfinder