Fill a clean 8 oz glass jar about halfway with dried arnica flowers. Pour your chosen carrier oil over the flowers until they are fully covered.
Let infuse for a day or up to a few weeks. The longer it infuses, the more the oil is able to absorb the beneficial properties from the arnica flowers. Give it a gentle shake every few days.
When done infusing the oil, strain the flowers out of the oil, keeping the oil.
Arnica Cream
Add shea butter to a stand mixer.
Whip on high for 1 minute, using the wire whip attachment. Then whip on low for 3 minutes.
Add the coconut oil and infused arnica oil. Whip on high for 1 minute, then on low for 3 minutes.
Add the essential oil if using.
Whip on low for one minute, or until the mixture is light and fluffy.
Notes
Essential oils are optional. Some great choices would be Lavender, Eucalyptus, Copaiba, Frankincense, wintergreen (for pain).
Any carrier oil will work for the infusion. I used avocado oil. Jojoba oil, argan oil, fractionated coconut oil are also great chocies.
This should last for around 6 months. There is no need for a preservative since no water is being introduced. Also, the essential oils will help act as a preservative. If it looks weird or smells different, throw away and start a new batch.