Making a citronella spray requires an empty spray bottle, water, oil, and citronella essential oil. All of these ingredients are easy to find, though citronella oil may need to be purchased at a specialty or health food store. Once the oil had been made, it can be used as an insect repellent or as a deodorizer. Insect repellants require true citronella oil and not an oil that merely smells like the citronella plant.
Citronella may me obtained in a number of different ways. If the plant grows locally, the leaves can be harvested and the oil collected by first drying the leaves completely and then steaming them until the oil seeps out. Gloves should be worn during this process, as citronella oil is quite potent and should not be handled in its pure form. Alternatively, the essential oil from the citronella plant may be purchased. Oils scented with citronella or an artificial citronella scent will not work as a citronella bug spray, though they can be used as an air freshener.
Aside from the citronella oil, the other ingredients in citronella spray are water and oil. The other type of oil, which can be olive oil or another type of vegetable oil, is used to cut the potent citronella oil, while still allowing a a substance that will stick to the surface it is being sprayed on to be formed. The water thins out the oil and makes the droplets smaller. Distilled water works well, as it does not contain any minerals or chemicals that could interfere with the chemicals in the citronella oil. Water and oil do not mix, so the citronella oil will need be shaken each time before it is used.
Making the citronella spray is a relatively simple process. The ingredients simply need to be placed in an clean, empty spray bottle, mixed, and then sprayed on or into the air. One part citronella oil to about 10 parts water and 10 parts olive or other oil is sufficient for a fairly strong citronella spray that is suitable as an insect repellant on humans or animals. If the spray is meant for use as a room freshener, the amount of citronella oil can be lowered to any amount that produces a pleasing odor.