Fizzy Bath Bombs 1 cup baking soda 1/2 cup citric acid 1/4 cup epsom salt, finely ground 2 teaspoons light oil - coconut, almond or olive 10-20 drops essential oil of your choice witch hazel as needed food coloring, optional flower petals or herbs, optional Combine dry ingredients. Add oils (and food coloring, if using) and stir to combine. Using a spray bottle spray a fine mist of witch hazel until the mixture can form a clump in your hand when squeezed. Don't use too much witch hazel, as it will react with the citric acid and cause it to start fizzing. (And I discovered by not having a spray bottle handy that you don't really need one. Just add a few drops of witch hazel at a time, and mix quickly when it fizzes.) Flower petals may be added to the mixture or put in the mold. Pack the mixture tightly into a muffin tin or silicon mold and allow to dry overnight.