Combine Baking Soda and Citric Acid: Mix the premeasured baking soda and citric acid in a mixing bowl until thoroughly blended.
Add Kaolin Clay and Mica (Optional for Coloring): Add the kaolin clay and mica into the mixture, especially if you wish to add color to your shower steamers. Blend these in thoroughly.
Incorporate Fragrance: Pour your chosen fragrance over the mixture, ensuring it's evenly distributed. Stir the mixture until the fragrance is fully incorporated.
Mist with Witch Hazel: Gradually mist the mixture with witch hazel while stirring continuously. Continue until you achieve the desired consistency. Aim for a texture where dropping the mixture from 6 inches above does not cause it to break apart, similar to the method used for crafting bath bombs.
Shaping Process: Scoop heaping piles of the mixture into your mold, then press down firmly to compact it. This step ensures the shower steamers hold their shape and density.