I will admit I have not made this yet but I am going to try as soon as I get everything. This idea is from Martha Stewart Via Pinterest. I don't think I will use the paper but it is a cute idea. I went to the local Dollar General Store and purchased silicone heart molds I think it will work. I am going to try this for my students at Sunday School and I will post the results.
Tools and Materials
Secret messages template
Igage waterproof paper
Spice or coffee grinder
Small spray bottle
Plastic wrap or plastic bags
Bath oil (or any light oil), optional
Bath salt, optional
Bath Fizzies How-To
1. Use your computer to download template and print secret messages on waterproof paper. This floatable paper is ink-jet and laser-printable, it uses most inks, and inks won't run on this paper. Cut out message and roll it up.
2. In a large bowl, combine 1 cup of baking soda and 1/2 teaspoon essential oil.
3. In a spice or coffee grinder, grind 1/2 cup citric acid, 1/4 cup bath salt, and 2 drops food coloring. Grind to a fine powder, and add to the mixture in the large bowl. Begin whisking together thoroughly.
4. To mixture, add a couple of sprays of water. It should reach a crumbly consistency.
5. Fill each half of a ball mold.
6. Add message to one half of ball.
7. Using hands, pack mixture in, slightly overloading. Press mold halves together. Let sit several minutes; unmold.
8. To dry the fizzies, place them on a kitchen towel and gently wrap with towel to dry for 24 hours. Wrap or package fizzies in plastic to protect them from moisture.
I found this on Amazon. It may work if you want the ball shape.
You could also use Epsom Salt I have read.