
Spy Dust (Nitrophenyl Pentadienal) - boredgamer2
https://en.wikipedia.org/wiki/Nitrophenyl_pentadienal
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jdietrich
A modern equivalent is SmartWater, a clear fluid that a) fluoresces under UV
b) is extremely difficult to wash off and c) contains a unique code for
forensic identification.

[https://en.wikipedia.org/wiki/SmartWater](https://en.wikipedia.org/wiki/SmartWater)

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totalZero
I don't see how such a product should verify ownership, and I agree with the
objection that a person can buy SmartWater and apply it to valuable items
owned by other people.

It is the high-tech equivalent of putting your thumb in the biggest piece of
pizza when your brother opens the box, to claim it as your own.

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xfitm3
Glo Germ powder is a consumer equivalent of this:

[https://www.amazon.com/gp/product/B00FE1RQA2](https://www.amazon.com/gp/product/B00FE1RQA2)

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oh_sigh
How exactly would it be used? Presumably you're using it to mark someone you
don't actually know, but then you need to actually go looking for the trail,
but how do you do that if you don't know who the spy is?

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sandworm101
1) Say you have a locked door to which you want the key. You put the dust on
the doorknob. Then you check the cars in the parking lot for traces. Now you
know which people have gone through the locked door and presumably have keys.
Checking their backgrounds also gives you a good idea what is happening behind
that door.

2) Before shredders got good. You put the luminol dust on the steering wheel
of an inteligence officer's car. Then you steel the shredded paper from the
base. The luminol then identifies which shreds of paper come from documents
handled by the inteligence officer.

3) You dope the inteligence officer's car again. Then you look at the door
punchcode panel to see which buttons he pressed. Now you are 90% of the way to
knowing the code.

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htfu
One of the sources also mentions tracking dogs, so it seems to have been quite
multi-purpose!

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sandworm101
Reminds me of sheep. Ever notice sheep with a colored mark on their back? They
hang a bag of colored chalk under the ram. This then leaves a colored mark on
the back of the sheep he has _serviced_.

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pacaro
Also known as _raddle_ not every Ram or Tup will tolerate a harness, so
sometimes powdered raddle is mixed with vegetable oil and smeared over his
chest.

It gives the farmer quite a lot of information, by changing the color every 17
days (a ewe's cycle), they can detect a infertile tup, predict lambing dates,
etc.

