The CIA released previously classified World War I-era documents Tuesday, and most had to do with invisible ink.

(However, in Peter Finn’s story about invisible ink, the weirdest method of passing messages apparently involved engraving them on toenails and then viewing them by using powdered charcoal. Engraving? On toenails? While they’re still attached? I don’t know.)

As Finn points out, a lot of us, inspired by Nancy Drew or the Hardy Boys, wrote “invisible messages” using lemon juice when we were younger. Many of those messages were probably used while playing spy — or to say, “I like you. Do you like me?”

But what would you write now? A love letter? A message to a friend? The things you think about people but don’t say out loud? The novel trapped inside you?

We want to hear what you’d write — and who you’d write to. Spouse? Friend? The cute guy you keep running into in the elevator? (Maybe not. Don’t want to weird him out.)

Leave a message with what you’d write, and to whom, in the comments.