http://www.newscientist.com/article.ns?id=dn7110%20
Anna Gosline
"Dirty cash is a criminal's dream, as it is almost impossible for the police to lift fingerprints from certain well-used banknotes.
But now a technique can reveal who has handled Australian banknotes, which, because they are made from polymer, are notoriously difficult to lift prints from. The technique is so good that it makes previously invisible prints left on a range of surfaces clear for all to see."