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During the American Revolution, invisible ink was an important method of communication for spies on both sides.

Ingredients and Supplies

Ingredients and Supplies

¼ cup baking soda ¼ cup water Grape Juice Paper Something to write with- a cotton swab, toothpick, or paintbrush all work well.

Recipe courtesy of the book Invisible Ink: Spycraft of the American Revolution by John Nagy

Step 1 - Mix

Mix ¼ cup baking soda and ¼ cup water.

Step 2 - Wet your brush

Dip a cotton swab, toothpick or paintbrush into the mixture.

Step 3 - Write your message

Write a message on a white piece of paper and allow it to dry.

Step 4 - Apply the decoding stain

Dip a cotton swab into grape juice concentrate or any dark juice and paint it over the invisible message.

Step 5 - Reveal the message!

Wait for your message to appear.

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