Invisible Ink

[im_funsized]

MI6 'used bodily fluids as invisible ink'
British intelligence services experimented with using semen as an invisible ink to write top-secret letters, it has been disclosed.
http://www.telegraph.co.uk/news/uknews/8015180/MI6- ( Read more... )

Comments

[im_funsized]

That's what I figured, but I think people trying to read your message would try UV light. They were all excited because semen didn't react to Iodine vapor.

[cain_iii]

duh! Blow it! It is a good way to get the semen to come out! :p