Weigh out all the ingredients.
Prepare a spot to set the finished bath bombs.
Mix the baking soda, citric acid, epsom salt and kaolin clay together.
Add the avocado oil, polysorbate 80 and fragrance oil. (You will need to use your hands to get this properly mixed).
Spray the mixture with witch hazel and mix with your hands. You are going for a consistency of wet sand.
Scoop a heaping pile of the mixture into each half of your mold.
Firmly press the mold together until it closes.
Slowly, take off the top of the mold. I found that gently squeezing the mold helps to release it.
Turn the mold upside down to release the bath bomb onto your wax paper.
Allow to cool for 24 hours.