Fun fact the best invisible ink has traditionally been semen. British intelligence switched to other stuff after their tabloids started making fun of them for it at one point, 20th century sometime idk. Lemon juice sort of works too, put a letter on a radiator and the invisible ink becomes visible.
Fun fact the best invisible ink has traditionally been semen. British intelligence switched to other stuff after their tabloids started making fun of them for it at one point, 20th century sometime idk. Lemon juice sort of works too, put a letter on a radiator and the invisible ink becomes visible.
I would like to know how they found it out in the first place
Teens trying to burn their overused socks, which briefly revealed phantom hieroglyphics
Genetically signed correspondence, neat!