This recipe uses what’s called the Digestion Method, where the herb and oil mixture is applied to a low heat warm water bath of 100 degrees Fahrenheit.
1/4 cup dried calendula petals
1 cup almond oil
Using a coffee grinder, powder the dried calendula petals as finely as possible. (Expect to need about 1 cup of dried calendula petals to yield 1/4 cup of powdered calendula petals.) Put into a sterilized jar of 1 pint or larger and add almond oil. Mix together either with a sterilized spatula or by gently swishing around. Make sure there is at least 1/4 inch of oil covering the top of the herbs. Cover the jar and place in the warm water bath. (Make sure the water line is slightly above the oil in the jar.)
Swish around the mixture periodically (approximately every 2-3 hours). If at any time, the oil is less than 1/4 above the herbs, add more oil to the jar. Continue to let sit in warm water bath for 10 days; check water line often. After 10 days, strain the oil into a sterilized dark glass jar. Let sit for a few days more to allow sediment to gather and strain again into a second sterilized dark glass jar for usage.