How to Write a Message with Invisible Ink

Do you want to write down your password so that no one can see it, or do you want to send someone a secret message? If you know how to write messages with invisible ink, soon you will feel like a secret agent.

Table of Contents

Invisible Squid with Lemon Juice

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Squeeze half a lemon into a bowl.

Add a few drops of water to the bowl. Use a spoon to stir.

Dip the tip of a cotton swab in the lemon juice solution and write the message on a piece of white paper. You can replace the cotton swab with a feather, toothpick, ink pen, paintbrush, or calligraphy pen.

Wait for the invisibility ink to dry. When the ink dries, your message will disappear.

Hold the paper with the invisible message over the light bulb or flame/candle. Hold the paper close to a light bulb or a flame/candle until the message reappears. Be careful not to get the paper too close if you’re using fire or candles.

Invisible Squid with Baking Soda

Dip the tip of a cotton swab in a mixture of 1/4 cup (60 ml) baking soda and 1/4 cup (60 ml) water. Write a message on a white sheet of paper with the tip of a cotton swab.

Milk Stealth Squid

Pour the milk into a shallow dish and dip the tip of the cotton swab into the milk.

Use the tip of a cotton swab to write a message on a white piece of paper. Wait for the milk to dry.

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Wait for the text to dry for about 30 minutes.

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Expose the notepad to a heat source. You can use a light bulb, a candle/fire, or an iron. Milk will heat up more slowly than paper, and this causes text to appear.

Invisible message written in white crayon

Use a white crayon to write a message on a white piece of paper.

Use watercolor and paintbrush to paint on the paper. The message will appear.

Invisible message without ink

This method is based on pressure and indentation on the paper.

Use two sheets of paper. Place one sheet on top of the other.

Write a message on the paper above. Use a pencil or ink pen to write the message with strong pressure.

Take out the paper above.

Using a pencil, lightly polish the paper underneath. The message will appear, similar to chalk written on a blackboard.

Advice

If you don’t have white wax, you can replace it with a white candle to write a message, then paint it with watercolor like you would use a crayon.
With the lemon juice method, black paper is best.
To read a message with lemon juice or milk, you can also place the paper under a piece of cloth and iron it to make the text appear. Another way is to put the paper in the oven at 177 degrees Celsius for a few minutes until the message appears.
With the white crayon method, you don’t necessarily have to paint on it. Hold the paper slightly tilted in front of a window during the day. You can’t see it clearly, but you can still read it, and it’s much simpler this way.
In the white crayon method, instead of coloring on the paper, you can also paint with a dark colored marker.
Make sure not to mix too much water.

Warning

Be careful not to burn or cause a fire when heating the paper.

Things you need

Lemon juice
Water
Small bowl
Spoon
Cotton swabs, toothpicks or paintbrushes
White paper
Light bulb
Baking soda
Water
Whisk eggs
Paintbrush
Grape juice
Milk
White wax pens
Water color
Rub

Steps