These are the fixed, non-volatile oils produced by the cold pressing of nuts, seeds and legumes. The are often used as a dispersant for essential oils and in cosmetics for their excellent moisturising properties. An oil which has not been refined to remove colour and odour by filtering or bleaching processes is know as a virgin oil and is generally considered to be the purest form. Unlike essential oils that are relatively stable over long periods of time vegetable oils are subject to oxidation and should be stored in airtight containers away from heat and light.