Question: how much polysorbate 20 to use in bath bombs?
Answer: 1 cup Baking Soda. 1/2 cup Citric Acid. 1/4 tsp. Finely Powdered Lavender (optional) 15 drops Lavender Essential Oil* 1/4 - 1/2 tsp. ...  Hydrosol As Needed. Solubilizer such as Polysorbate 20 or Solubol.