Look for pomace grade olive oil in the grocery store or purchase from a soap making supply company. This lower grade oil is preferred for soap making and produces a higher grade soap. Purchase lye in the hardware store. It is often behind the counter due to its caustic nature and the fact that it can be used in processing street drugs. If you cannot find lye, purchase drain cleaner that is 100 percent lye with no additives.

Prepare soap molds by lining with waxed paper or spraying with nonstick cooking spray. Soap molds are available in craft stores and come in a wide variety of shapes and sizes, but any plastic container will do. Plastic storage containers or even cardboard boxes are suitable for molding soap that will later be cut into bars.

Measure the water and lye carefully and do not alter the proportions. Too much lye will produce a soap that is damaging to the skin. Pour the water into a heat proof container; the chemical process activated when you combine water and lye causes the solution to heat up rapidly. Stir constantly to completely dissolve the lye. Avoid inhaling fumes released during the process. Set the solution in a safe place to cool.

Measure the oil and heat to 100 degrees F over medium-low heat. Do not leave the oil unattended. Pour the heated oil into your soap making bowl and add the lye solution by pouring a thin steady stream into the oil. Stir constantly with a wooden or stainless steel spoon. A chemical reaction will cause the lye and oil to sopanify and become thicker, rendering the lye harmless. The process may take 10 minutes or more to complete. When a small amount of the mixture leaves a visible ridge on the surface when dropped back into the mixture, it has attained trace and is ready for the addition of fragrance.

Add the lavender sage oil and stir briskly as some fragrances will cause the soap to harden quickly. The amount of fragrance needed depends on your personal taste and the concentration of the oil. Always refer to the manufacturer's directions for the proper amount.

Pour the soap into your prepared soap mold and cover with a cloth. Allow the soap to set for 24 hours. Remove the soap from the molds by gently twisting the mold and popping the soap free. Wrap with tissue paper or plastic wrap and store in a cool dry area to cure for 3 to 4 weeks before using.