Boiled Kitchen Soap: Dissolve 2 1/2 lbs commercial lye in 5 quarts cold water. Cool slightly, then add 10 pounds tallow. Bring to a boil over low heat and boil, stirring, until it saponifies. Pour into molds and let set one week before turning out. This soap should be aged 3 to 4 weeks before using. It is best after several months.
Transparent Soap: Any good white neutral soap may be made transparent by reducing it to shavings, adding one-half its volume of alcohol and setting the mixture in a warm place until the soap is dissolved. When allowed to cool, the soap has somewhat the appearance of rock candy. It may be perfumed as desired.
Cosmetic Soap: Any neutral hard white soap may be used as a foundation for toilet soap by shaving the soap thin. Melt in a double boiler with distilled water to the proportion of 6 lbs soap to 1 pint water. Add 2 oz salt. Boil down, allow to cool and cut into squares.
Borax Soap: Dissolve 3 oz borax in 2 quarts boiling water. Shave 2 lb pure white hard soap and add. Stir and simmer over low heat until ingredients are thoroughly melted and mixed. When cold, soap is ready for use.
Camphor Soap: Dissolve 1 lb neutral hard white soap in 1 cup boiling water. Continue boiling over low heat until soap is the consistency of butter. Add 6 oz olive oil mixed with 1 oz camphorated oil. Take from heat and beat with egg beater until a complete emulsion forms. Use to clean scratches.
Iodine Soap: Dissolve 1 lb white castile soap shaved fine in 3 oz distilled water. Add 1 oz tincture of iodine. Put in double boiler, melt and mix by stirring.
Source: "Making Soaps & Candles" by Phyllis Hobson