Place your dried calendula flowers in a clean, dry glass jar, filling it about two-thirds full.
Pour in enough carrier oil (such as extra virgin olive oil) to completely cover the flowers.
Gently stir to release air bubbles and ensure all the flowers are coated in oil.
Secure the lid and place the jar in a saucepan lined with a folded tea towel. Fill the pan with warm water so it reaches at least halfway up the jar (but not the neck).
Heat on very low and let the oil infuse for 2–4 hours, keeping the oil warm but never hot.
Remove from heat and allow to cool slightly, then strain the oil through a fine mesh sieve (lined with cheesecloth for a clearer oil) into a clean, dry jar.
Let the flowers sit in the sieve for about 30 minutes to fully drain.
Store your calendula oil in a tightly sealed jar in a cool, dark place, away from sunlight.