Calendula is one of those staple herbs for my garden, and even after downsizing from a decent-sized yard to a balcony, I still insisted on growing it this year. I like to use it in magic of course, but I also like to make an infused oil with it.
The oil of calendula is great for many things, but I like to use it in both salves and bars for chapped skin, minor cuts, bug bites and I find when used with other herbs, it is quite effective on sore muscles.
Before starting the oil infusion I dry the flowers so there is a lesser chance of the oil going funky. For the actual oil I used grapeseed oil this year, but olive oil or perhaps almond oil work fine as well. My calendula oil is still infusing, and I will let it sit in a cool, dark spot for about a month. I shake it about every other day.
Once it is finished infusing I will strain it through cheesecloth to separate the flowers from the oil and bottle up the oil again until it is ready to use.
To a see a great herbal infusion tutorial, head on over to the Mountain Rose Herbs blog. They also have some great recipes on how to use your calendula oil once it's ready.