Castor oil is a multi-purpose vegetable oil that people have used for thousands of years. The essential fatty acids that castor oil contains help in restoring the skin's natural moisture balance. Apply castor oil gently on your face and massage in circular motions. You can even leave it overnight and wash off in the morning. You can also use steam to open your pores and help your skin absorb the oil better. It's commonly used as an additive in foods, medications and skin care products, as well as an industrial lubricant and biodiesel fuel component.