A tangy, spicy oil that is used in cooking, in the beauty industry, and in religious ceremonies. Mustard oil is made from the mustard seeds of the mustard plant. The seeds are soaked in water for three days, then boiled in an iron pot for up to four hours. This oil is popular in Indian cooking, but can also be used in Middle Eastern and African dishes. It is often mixed with other oils to give it a less intense flavor. Mustard oil is also used in the beauty industry to cleanse and massage the skin. It is also used in religious ceremonies, where it is mixed with water and poured over the head of the participant.