Diy Invisible Ink Uv. Get a highlighter, pliers, hot water, empty cup, a uv/ black light, and a water tight jar. Squeeze both halves of your lemon over the bowl.
Don't destroy the highlighter trying to get it open. You can use lemon juice, milk, baking soda, cornstarch and iodine, and a white crayon. Invisible ink with lemon juice making invisible ink is a lot of fun, you can pretend you are a secret agent as you keep all your secret codes and messages hidden from others.
To make an invisible ink message that will be revealed by heat, first pour 1 teaspoon (5 ml) of lemon juice into a small bowl.
I’m putting that to the test. Using invisible ink is a cool way to hide your messages until its time for them to be read. Set the iodine aside for later. Painting the tonic water on paper under a uv blacklight and testing with a uv flashlight occasionally.