When sourcing soap chemicals, you must focus on three core categories: Surfactants/Base Oils, Neutralizing Agents, and Functional Additives. For solid soaps, Sodium Hydroxide (Caustic Soda) with a purity of 99% or higher is critical. For liquid soaps, Potassium Hydroxide is the standard. Base oils like Palm Oil, Coconut Oil, or Glycerin should be checked for Free Fatty Acid (FFA) levels, as high acidity can spoil the final product. Additionally, ensure surfactants like SLES (Sodium Laureth Sulfate) have an active matter content of 70% for optimal foaming performance.