Doesn't appear to defeat security envelopes either, which have been
   around for quite some time.

   > -----Original Message-----
   > From: David Honig [[1]mailto:honig@sprynet.com]
   > Sent: Thursday, December 14, 2000 2:06 PM
   > To: R. A. Hettinga; cypherpunks@algebra.com; cryptography@c2.net
   > Subject: Re: Perry's Paint Fable comes to mind...
   >
   >
   >
   > At 03:50 AM 12/14/00 -0800, R. A. Hettinga wrote:
   > >> FOR ALL TO SEE
   > >> It's a spray which renders sealed envelopes transparent, making
   the
   > >> letters inside as easy to read as postcards. "It leaves an
   > odour for 10
   > >> to 15 minutes," says the spray's inventor, but, apart from
   > that, "no
   > >> evidence at all" that it's been used. While the
   > manufacturer describes
   > >> "See-Through" as a "non-conductive, non-toxic, environmentally
   safe
   > >> liquid", human rights activists believe "it's an ethically
   > questionable
   > >> product" which could tempt security forces to bend laws.
   > >> [2]http://www.newscientist.com/news/news.jsp?id=ns226930
   > >
   > >[Lighter fluid and similar stuff works just fine. That's been known
   > > for over a hundred years... --Perry]
   >
   > Wouldn't this be detectable if you scrawled on the envelope with
   > an ink succeptible to paper chromatography in that solvent?
   >
   > You can make primitive (before cheap float glass) windows by
   > oiling paper...
   >
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References

   1. mailto:honig@sprynet.com
   2. http://www.newscientist.com/news/news.jsp?id=ns226930