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Strongly associated with grade school and spy novels, invisible ink carries with it a sense of youthful excitement and mystery. Whether you are sending a message across the room or across an ocean, the same techniques apply.

There are a number of different ways to create invisible ink. The simplest types are made with a liquid that is heat sensitive. Of all the options, lemon juice works the best. Here is a simple recipe:

INVISIBLE INK RECIPE #1:

Ingredients: Lemon juice

Equipment: cotton swab or toothpick
heating pad, light bulb (in lamp), or hot iron
piece of writing paper

Directions: To create the message: Dip the cotton swab or toothpick into the
lemon juice. Rub the cotton swab or toothpick against the paper to
write your message. Be sure your "pen" stays moist.

To decode the message: hold the paper near the heat source until the message appears. The message will appear in brown.

Using a slightly more complicated recipe is rewarded with a striking blue message.

INVISIBLE INK RECIPE #2

Ingredients: cornstarch
water
iodine
cotton swab or toothpick

Equipment: cooking source (microwave, stove top, etc.)
container (2)
sponge

Directions: To create the message: Mix cornstarch and water over heat
briefly. After it cools, down, write your message.

To decode the message: Mix the iodine and water. Dip the
sponge into the mixture, and gently rub the paper with the
invisible message

This will give you a dark blue message on light blue paper. If
you substitute lemon juice for the cornstarch you will get
white writing on a light blue background.

Or, you can create a message with pink writing. Be careful not to get any of the mixtures in your eyes!

INVISIBLE INK RECIPE #3

Ingredients: 5-6 laxative tablets containing Phenolphthalein
Water
4 teaspoons of washing soda or ammonia

Equipment: measuring spoons
container for mixing
plate
cotton swab or toothpick

Directions: To create the message: Crush laxative tablets and mix with
a few tablespoons of water. Write your message.

To decode the message: Mix 4 teaspoons of washing soda
or ammonia with 4 tablespoons of hot water. Pour water
onto the plate, and lay the message in it. When the paper is
thoroughly soaked, drizzle the mixture onto the paper. A
pink message will appear.

Learn more about this author, Frances Simon.
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