I use polysorbate in my bombs to allow the oils to disperse better in the water. I find it makes for a cleaner tub after. My recipe is very simple, citric acid, backing soda and an oil/butter mixture along with fragrance. I make sure that nothing with water or alcohol is added, as once the fizzing reaction starts, it is hard to stop. My bombs are hard without which hazel, so I never use it. Work when it is not humid, work dry, and use just enough oils that the mix stays together while pressed, but does not feel wet and you are there.