This oil is beneficial for those who are prone to cold and cough as it helps clear the congestion of chest and nose. Apply a mixture of one teaspoon of mustard oil and camphor on the chest and lie back to enable the vapors to enter the lungs. For mustard oil steam treatment, add a few spoonfuls of mustard oil and caraway seeds to a pot of boiling water and inhale this steam. The strong aroma of mustard oil will warm up the respiratory system, thus providing protection against the formation and build-up of phlegm.