Homemade mustache wax is simple and easy to make. Though mustache wax is used less commonly today than in its heyday, it can still help provide a sleek, stylized look that may be useful in certain situations. Homemade mustache wax can be made in less than one hour, though it will need some time to harden and coagulate before it can properly be used. Homemade mustache wax will keep for about six months if stored in a cool, dark place between uses. Combine the grated beeswax and castor oil in a heat-proof container. Heat the mixture in the microwave on high for two minutes or until the beeswax is completely liquefied. Stir the mixture with a wooden spoon or glass stirrer. Add the sandalwood essential oil and stir to combine. Transfer the mustache wax to a small wide-mouth glass container with a tight-fitting lid. Let the wax cool completely before first use.