Place a handful of bruised leaves into an amber-colored jar and fill it to the top with a high-quality plain cooking oil. Put a lid on the jar and leave it in a dark, cool place for four to six weeks. Decant as necessary into a smaller squeeze bottle for use.
Tea tree leaves can be quickly infused into oil on the stove. Place the bruised leaves and enough oil to cover them in the top half of a double boiler with water in the lower half. Simmer at a medium temperature for eight to 12 hours. Once the oil is cool, strain out the leaves and decant the oil into an amber jar. Decant into a smaller squeeze bottle for use when required.
A fast method to make an infused oil is to simply add three to five drops of tea tree extract to 30 milliliters of base oil and shake to combine. Traditionally, tea tree oil is extracted from the leaves using a steam distillation method omitting the oil.
Be careful when working with hot oil and do not allow it to boil. Amber jars work best because they limit sunlight reaching the oil, which degrades the tea tree properties. Do not use tea tree oil on animals.