Carrier oils would be used as a base oil to which your favourite essential oil is added, before use on the skin. This is to dilute the concentrated essential oils and making it more safe to use.  Different carrier oils have their own benefits, and below you can find some of the more commonly used and known.  These are the ones that I’ve personally used on myself, and tried out without side effects.

Sweet Almond Oil – good for dry skin and itchiness

Avocado Oil – nourishing, antioxidant, good for skin regeneration (e.g. dry, cracked skin or eczema prone skin)

Coconut Oil – nourishing, cooling, blends well with other oils

Jojoba Oil – anti-inflammatory, regenerative skin care, great for hair and nails.

There are of course more carrier oils available such as Arnica, Rose hip seed, grapeseed or Apricot Kernel 

Avoid Mineral Oil

Mineral oil and petroleum jelly are byproducts of petroleum production. They are not of natural, botanical origin and are not used within the scope of holistic aromatherapy. Mineral oil is used in baby oils and many commercially available moisturizers because it is an inexpensive oil to manufacture. What goes against these is that they can clog pores, prevent absorption of essential oil, prevent toxins from leaving the body through the natural process of sweating, and possibly block vitamins from properly being utilized.

Storing Carrier Oils

For fragile carrier oils or for those that you will be keeping for a long duration, store them in dark glass bottles with tight fitting tops, and store them in a cool, dark location. Often shops where the oils are for sale, will have empty storage bottles available for sale or will sell the oils in such containers.

If you will be using up an oil quickly, it really doesn’t need to be transferred to dark glass. When you purchase carrier oils, the supplier may have packaged it in a plastic bottle, to save on packaging and shipping cost. Many of their customers also use up the oils shortly after purchase. Unlike with essential oils which should always be stored in glass (essential oils can dissolve the plastic), carrier oils can be stored in plastic.

Most carrier oils can be stored in the refrigerator, and this can help prolong the lifespan of fragile oils, but not all can take the freshness of the fridge. Avocado Oil, for example, shouldn`t be stored in the refrigerator. Oils stored in the refrigerator may solidify or turn cloudy and will need time to return to room temperature prior to use.
Carrier Oils and Rancidity

Essential oils do not go rancid. Carrier oils, however, do become rancid over time. The level of natural fatty acids, method of extraction and other characteristics of an oil all can affect how quickly an oil goes ‘bad;. If you come across a carrier oil that has a strong, bitter aroma, it may have gone rancid. If you can, compare the aroma of the oil that you suspect is rancid with the same botanical oil that you know is fresh.

Carrier oils that you purchase should be natural and pure. Exceptions include buying carrier oils that have natural Vitamin E added. Vitamin E, often listed as ‘tocopherols’ acts as a natural preservative.

 

(Source: http://www.naha.org | Most common base oils used in aromatherapy)
(Source: http://www.aromaweb.com ¦ What are Carrier oils?)