In a large mixing bowl, mix the baking soda, epsom salts and citric acid until well combined.
If you want to make more than one color of bath bombs, divide the mixture between 2 (or more) mixing bowls. I divided mine into two. Add about 10 drops of essential oils to each bowl (when using 2 bowls). Using a fork to blend it into your mixture. Add about 1 teaspoon of mica powder to each bowl (if using 2 bowls). Stir until color is well combined. The color will darken more after you add the witch hazel, so don't go overboard or you'll be scrubbing the mica from your tub.
Spray the mixture gently with witch hazel, then mix with your hands to incorporate. Keep spraying and mixing until you get to a point where it's starting to clump, but is still dry. You don't want it to get sticky. It should crumble like kinetic sand. If it's too wet, it will expand and make it really hard to get it to set up properly.
Spray your bath bomb molds with olive oil spray. Then press your bath bomb mixture down into your bath bomb mold, leaving space for the hidden surprise.
Add the toy, then pack in more of the bath bomb mixture.
Fill the other side of the mold with the mixture, then spray both halves lightly with witch hazel. Press the halves together, making sure the mixture is pressed well together. Allow the bath bombs to sit for about an hour, then carefully remove them from the molds and set them out to cure. Let them cure overnight or for 24 hours until they're completely hardened.
How to Use Bath Bombs for Kids
Pop one in the bath for bath time. They will start fizzing right away.
Your kids will love the surprise they find!
Print the recipe again: DIY Toy Surprise Bath Bombs for Kids https://www.happy-mothering.com/diy-dino-discovery-bath-bombs/