Heat oil and coffee in a double boiler (or saucepan / bowl combo) over low heat for 1 hour.
Let cool, strain well and transfer to a storage bottle.
Notes
Your coffee-infused oil should keep for a few weeks. I prefer to store mine in the refrigerator to keep the oil as fresh as possible, but it's not necessary. And feel free to use other oils if you prefer. Almond oil is nice because it has amazing skin benefits and will remain liquid, unlike coconut oil. But you can get similar benefits from jojoba, grapeseed, and olive oil.