Making infused oils is fairly simple. To do so, you'll need some carrier oil - either sweet almond or grapeseed1 - as well as a jar with a tight-fitting lid, some small dropper bottles, labels, a small funnel, extra storage bottles (just in case), herbs of choice, muslin and patience.
(Using lavender as an example).
The flowers should be cut just before they open, and on a warm day after the dew has dried, but before the day gets too hot. (If you're using leaves rather than flowers, they can be left until midday, when the aromatic oils are at their highest.) They'll need to be dried, so either tie them into a bunch or lay them on a cake rack and put them into an airing cupboard or a well-ventilated room.
Creating the Oil
When they are finished drying, take all the small flowers off the stems and place them inside the jar with the tight-fitting lid. Pour the carrier oil over the flowers slowly, allowing the air bubbles to come to the surface. When the flowers are just covered, put the lid on and give it a shake. Leave it for about a week in a dark place, and turn it occasionally after giving it another quick shake.
After the week is up, you'll need to strain it. The easiest way is to have another jar, with a screw-top lid, or a small jug and an elastic band. Put the muslin over the top of the clean and dry jar, and hold it in place with a rubber band, allowing it to dip in the middle. The dip must be deep enough to take the amount of flowers that you have and not be touching the oil at the bottom, or sticking out of the top.
Pour the flowers slowly into the muslin. This will be a bit messy, so make sure that you have a towel underneath the jars, and are not rushed. When all the flowers and oil are out of the jar, then you can put it away for washing up. Put the lid on - or otherwise cover the jar over the top of the muslin - and leave it overnight to drain. If it is your first time, you'll probably be in a bit of a mess right about now, so wash the oil off with neat washing-up liquid or hand cleaner. Don't use water until everything has been covered, otherwise it will just slide over the oil.
The next morning the muslin can either be thrown away with the flowers in it, or rinsed and washed for use again. In either case, pour the oil into as many dropper bottles as you have, and then into the storage bottle if there is any over. The storage bottle should be dark to keep the light out, or kept in the dark if clear.
Uses of Infused Oils
Other infused oils can be made from plants and leaves, and they are all made the same way, but keep in mind that these will smell differently than the ones you can buy in shops, since they're made differently - and some would say they smell better. Here's what they're best used for:
Lavender - relaxing, sleep inducing.
Rosemary - stimulating; can be added to water and used as a rinse for dark hair.
Chamomile - soothing; can be added to water and used as a rinse for fair hair.
Peppermint - can be used directly on bruises, sprains and toothaches.
Sage - a few drops in warm water can be used as a facial steam to cleanse and refine skin.
Thyme - oil made from flowers and leaves and put in water, which can be used as a skin tonic.
Remember, these uses are for home made infused oils only. It is not recommended that manufactured essential oils are put directly onto the skin.