Making your own shampoo can be an economical alternative to buying commercial shampoo and is ideal for people who want to know exactly what they're adding to their hair, as well as for those who like to customize the scent of their shampoo or its hair-cleaning properties. Castile soap flakes are most commonly used for homemade shampoo. Castile is a soap made from vegetable, coconut, soybean or olive oil. An alternative to castile soap are the shavings from any bar of soap that you have at home.
Heat 1 quart of water just to boiling in a dutch oven or large pot.
Combine 4 ounces of soap flakes with the water. If you don't have pre-flaked soap handy, use a large cheese grater or a sharp knife to cut off tiny flakes of bar soap to dissolve in the hot water. Stir the mixture over a low heat with a wooden spoon until the soap flakes dissolve.
Stir in any optional additives, if using. Add 4 to 8 drops of an essential oil such as lavender for a calming shampoo, or peppermint for an invigorating shampoo. Allow the mixture to cool completely.
Pour the mixture into an empty shampoo bottle or clean 1/2 gallon container that is handy for use in the bathroom. The mixture will be denser than commercially prepared shampoo -- use a container with a nozzle that will accommodate the thicker flow.
Make a conditioning shampoo by taking 1 cup of your prepared shampoo and mixing it with 1/4 cup of olive oil or almond oil. Stir well and pour the mixture into an empty shampoo bottle or other appropriate container.