Inhalation: One can simply unscrew the top and take a whiff from the bottle.

Evaporation: The oils are placed in open containers in a room and allowed to evaporate into the air. This process can be speeded by heat, for example by putting the oils into a ring placed on a light-bulb or into water over a candle flame.

Diffusors: These are little machines which blow air through a pool of oil to make it evaporate and diffuse into the air faster.

These techniques that disperse the scent into rooms can be used to set an emotional tone in a room, whether one wants that to be relaxing, spiritual, celebratory, or mentally focussed. They can also be used to kill germs in the air during cold season.

Steams: The oils may be placed in a well in front of a humidifier or they may be placed on boiling water and breathed with a towel placed over the head. Use 2-5 drops in a bowl of hot water. These techniques work well for clearing the nose during a head-cold. Presumably they could also be used in steam rooms.

Misters: The oils can be put into misters or spray bottles with water and sprayed in the room or directly onto the skin. Use 8-10 drops to an ounce of water. Some people put a bit of shampoo or vinegar into their misters to help disperse the aromatic compounds in the water.

Baths: Warm baths are a very efficient way to use essential oils. Warmth makes them evaporate quickly for inhalation and also opens the pores so the oils can be absorbed directly through the skin. Use 10 drops in a tub of water. If you are using very warm oils in a bath, it may be wise to mix them in a carrier oil first, because they can float on the water and come into contact with the skin undiluted otherwise.

The oils can also be used very efficiently in foot or hand baths or sitz baths. Use less oil depending on the size of the bath. One of my favourite treats is a foot bath with peppermint and lavender oils and a good foot massage.

Compresses: The oils are put into hot or cold water and a cloth is soaked in the mixture and then placed over the desired body part. Cold compresses with lavender and chamomile are great for headaches, hot compresses with eucalyptus or juniper for muscles aches.

Massage: Probably everyone's favourite way to have the oils applied. Mix 10-15 drops of oils in one ounce of a good quality vegetable oil such as almond, grapeseed or jojoba, and use in a massage.