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
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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