Soap is made from oil and caustic soda by boiling and processing. Soap contains about 30% moisture. If it is dried, it will not only make the water evaporate and shrink and dry, but also separate the internal oil from caustic soda. As a result, the oil becomes acid fat, and caustic soda becomes soda ash by absorbing carbon dioxide in the air, thus reducing the decontamination ability of soap.
?
It is the moisture in the soap that combines grease with caustic soda