This is the most common of all cheating techniques, and occurs in 99% of cases. Extremely foul-smelling low grade oud oils are spiked and tamed with essential oils like vetiver or fennel oil. The use of synthetic perfumes is not uncommon. Almond oil, DPG and glycerin are used to stretch the oud oil, and some distillers even use a certain type of synthetic glycerin which is harder to detect, to stretch the oil. Certain powders are used in the distillation process itself to make the oil thicker, which a lot of people incorrectly think is an indication of quality.