Secret messages, treasures maps, and notes that big brother or sister isn’t allowed to read – those are a few of the many reasons why young kids need to know how to make invisible ink! Luckily for Mom, it’s easy, non-toxic, and shouldn’t make a big mess. You only need two ingredients – baking soda and water.
Step 1. Mix equal parts water and baking soda.
Step 2. Dab a cotton swab, toothpick, or paintbrush into the mix.
Step 3. Write a message onto white paper using the baking soda solution as the ink.
Step 4. Allow the ink to dry thoroughly.
Reading the message is easy, and there are two ways to do it. The first is to hold the paper up to a heat source. An incandescent light works perfectly for this. The baking soda will cause the writing on the paper to turn brown.
The second option is to paint over the message with purple grape juice. The message will appear in a different color than the juice.
The instructional portion of this article was provided by wikiHow, a wiki building the world’s largest, highest quality how-to manual. Please edit this article and find author credits at the original wikiHow article on How to Make Invisible Ink. Content on wikiHow can be shared under a Creative Commons License.