It is important to preserve homemade beauty products, such as creams for your face and hands, so that the products last more than a couple of weeks, and bacteria doesn’t grow.
I think that the easiest way to preserve kitchen cosmetics is to use grapefruit seed extract, found in health food stores, and used by some personal care product manufacturers such as Aubrey Organics. This choice would be expensive for producing gallons of creams and lotions, but for small batches it is by far the most convenient. Use 6 drops per ounce of cream of oil, or 1/3 teaspoon per cup. You can also use antiseptic essential oils such as rose, clove, rosemary or lavender. Only use small amounts. Per ounce of cream or oil, use 3 drops or less (eye area), 5 drops or less (face), or 25 drops or less (body).