Absolute oils are usually the most potent, concentrated and aromatic of all aromatherapy oils. Whereas essential oils are typically extracted via steam distillation, absolute oils require the use of solvent extraction or more traditionally, enfleurage. This process tends to be used for the most fragile plant materials where steam distillation would distort the delicate perfume, or with plants that contain only small amounts of essential oil. The efficiency and low temperature of this extraction process helps prevent damage to the fragile fragrant compounds, and results in an oil that contains non-volatile waxes, plant dyes, as well as the essential oil itself. Absolute oils are commonly used within aromatherapy perfumery and can also be diluted and used in the same way as any other essential oil. They are much thicker and more viscous than essential oils and should be used in lower concentrations due to their stronger perfume and therapeutic powers.