There are numerous methods for making your own oils. Cold pressing works for products like olives and grapes, and chemical extraction requires quite a bit of laboratory equipment and know-how. Distillers have been making liquor for generations and it can work for oils too, but distilling involves extra equipment. Instead, try the "chicken soup" method (without the chicken and vegetables, of course). Sassafras oils are found in the bark of the roots of sassafras trees. The trees grow in the wild all over the northeast, southeast, south and southwestern United States and elsewhere in the world. Sassafras is commonly used to make tea, but that's not the oil. The essential oil, commonly used in aromatherapy, is also known as a bug repellent. The oil has a sweet-spicy pepper smell with a hint of underlying wood or earthiness. The dried bark contains about 10 percent oil.
Track down some mature sassafras trees. Locate the main roots from the trunk and, using a shovel, dig to where the root is at least 2 inches thick. Dig around the root, clearing it of dirt and use an ax to hack out a section of root. Don't take more than one section from each tree. You don't want to kill the tree. It will grow more roots, but not if you take them all first.
Remove the bark from sections of root using a potato peeler or a sharp knife. Place the shavings in a colander and and rinse thoroughly to remove the dirt. Set the colander, root bark and all, over a bowl and let stand. The holes in the bottom of the colander will not only allow the water to drain, but will later serve to help air circulation to dry the bark. After all water has drained, allow the drying process to begin. Occasionally toss the bark, moving the wet inner bark to the top for better air exposure. The complete drying process could take up to two weeks.
Place the dried bark in a pot and cover with water, about an inch more than the layer of bark. Put the pot on the stove and simmer for four to six hours to extract as much oil as possible. Since the oils aren't as dense (heavy) as water, when you are done simmering, the fat will naturally rise to the top. Let cool to room temperature and place the pot in the refrigerator overnight. Sometimes it will take a little longer for the oils to congeal as a separate layer from the bark broth underneath. Give it the time it's due; don't rush it.
Remove the pot from the refrigerator and, using as flat ladle, skim the congealed and hardened oils from the top of the bark broth below. Be careful to lift just the layer of oils, leaving behind the bark broth, which you can discard. Place the hardened oils in another pot and put the pot on the stove. Warm the oils until they again become liquid. Once warmed and in liquid form, pour through several layers of cheesecloth to remove any impurities through a funnel into a long-necked bottle. Cap or cork the bottle. The oils are sensitive to oxygen and will oxygenate and spoil with exposure to light and air.
Store the oil in a room-temperature, dark location and it should last unspoiled for at least four to six weeks. Use the oil for aromatherapy, or rub it on your skin before venturing outside on warm summer days for use as an insect repellent.