... soap-stock made entirely from beef tallow the most suitable for the purpose, but in practice found that the best results were obtained by using a superfatted soap made from a blend of one part of olive oil with eight parts of beef tallow, saponified with a mixture of two parts of soda to one part of potash, sufficient fat being employed to leave an excess of 3 or 4 per cent. unsaponified. ... — The Handbook of Soap Manufacture • W. H. Simmons
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