How to Create Invisible Ink

Invisible ink is a handy thing to have around. It's fascinating to children, of course, but it can be extremely useful to adults! For instance, you could write down your password or other "secret" information with invisible ink and place it in your wallet, or pocket, and even if someone were to come across it, to them it would be just a scap of paper. They might throw it away at best, but the odds are extremely low that anyone would even think of the invisible ink possibility.. not in this day and age where everything is high-tech and super-complicated.

Ingredients
The Creative Process
Making It Visible
Possibilities & Tips

Ingredients

Lemon
Toothpick or
Thin paintbrush or
Cotton swab

The Creative Process

Squeeze the lemon juice. You're done! You see, there is no need to keep invisible ink in storage. Just make sure you have lemons around, for emergencies and such. By the way, if your lemon juice is too thin, you can add a bit of sugar to it.

You can also use other ingredients instead of the lemon, like vinegar or onion juice, however the lemon is the most effective.

To write down your invisible message you can use a toothpick, a paintbrush (if you are used to it), or a cotton swab (for a slightly thicker effect). If you use a toothpick, allow the tip to soften in the lemon juice a bit before you attempt to write with it.

Making It Visible

To turn the invisible back to visible, and make your message reappear, you use heat. You can iron the piece of paper, place it close to a light bulb, or use your hair dryer. You can probably think of a variety of ways to bring heat to that paper.

Tip: An open flame is not recommended. Use other, less flammable, options. Also, no matter what you use, make sure you are close to water, just in case.

Possibilities & Tips

If you want to write down sensitive information, for your eyes only, use invisible ink. However, don't leave the paper intact. To make it more realistic, write something else on the paper, with a regular pen or marker. Just make sure you don't write in the same spot where you previously used your invisible ink. It might be a safer bet to first write with a regular ink, and then write your invisible info down. You could also wrinkle up the paper a bit. Make it look like something that accidentally wound up in your pocket, and is basically meaningless. Better yet, the plainly visible text should have some meaning. It shouldn't seem fishy or questionable.
PS: If you use invisible ink, and then place the paper in your super-safe place, it will actually be more suspicious and probably get more attention, than if it is located somewhere semi-obvious, but still private.