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In another, attributed to Aeneas the Tactician, a message hides dots of invisible ink over certain letters, which spell out the true message.

Meanwhile, Nina has always lived as if in invisible ink.

Dasch's handkerchief held the names of the saboteurs' contacts in America, written in invisible ink.

They were taught how to make more invisible ink using things like aspirin and Ex-Lax.

Each match was actually a pen that wrote with invisible ink.