For teachers, parents of young kids and playful folks: Can you tell me how to make and use invisible ink?

I did this as a kid. Water and lemon juice. Heat the paper with a hair dryer after the juice dries and it will show what’s written.

When my sister and I were kids, we had great fun writing secret notes to each other using the lemon juice and heat source invisible ink method. Lemon juice dries clear on paper but turns brown and readable when heat (in the form of sunlight or a light bulb) is applied.

There’s one other way you can do it. Write on the top sheet of a pad with firm pressure. Throw away the top sheet and send the second sheet. The recipient can lightly shade the second sheet with the side of a pencil and the words will appear.

What do you use as a pen?

We used popsicle sticks as kids… but if you’re looking for something more grown up, a glass pen like this would work.

The pen can be as simple as a toothpick or a small brush.

Use a quill plucked from the arse of a dodo.

^^^Bet you didn’t write very many invisible ink letters.

^^Only when my pen ran out.