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Non-toilet soaps

So-called metallic soaps are key components of most lubricating greases and thickeners. A commercially important example is lithium stearate. Greases are usually emulsions of calcium soap or lithium soap and mineral oil. Many other metallic soaps are also useful, including those of aluminium, sodium, and mixtures thereof. Such soaps are also used as thickeners to increase the viscosity of oils. In ancient times, lubricating greases were made by the addition of lime to olive oil, which would produce calcium soaps. Metal soaps are also included in modern artists' oil paints formulations as a rheology modifier. Metal soaps can be prepared by neutralizing fatty acids with metal oxides:

A cation from an organic base such as ammonium can be used instead of a metal; ammonium nonanoate is an ammonium-based soap that is used as an herbicide.

Another class of non-toilet soaps are resin soaps, which are produced in the paper industry by the action of tree rosin with alkaline reagents used to separate cellulose from raw wood. A major component of such soaps is the sodium salt of abietic acid. Resin soaps are used as emulsifiers.