I have african black soap in liquid state to which I’ve added some castor oil for extra moisturizing properties & to make it creamy. Sometimes some of the oil separates out after standing a while. This didn’t happen with my first few batches. What would be the best natural solution to keep the oil from separating as it is part of my natural skincare line? Would I need an emulsifier? The liquid soap also goes thinner because of the added ingredients. Would adding salt (NaCl) be enough to increase the viscosity of the mixture? Advice is greatly appreciated.