Infuse the calendula: Place dried calendula in a heatproof jar and pour in olive oil until the petals are fully submerged.
Heat gently: Screw on the lid and place the jar in a small saucepan lined with a folded cotton towel and filled with water. Warm over very low heat for 2–4 hours, keeping the oil warm but never hot. Stir occasionally and ensure the calendula stays submerged.
Strain the oil: Remove the jar from the water and let it cool slightly. Strain the oil through a fine-mesh sieve into a clean, dry jar, discarding the petals.
Add beeswax: Add beeswax to the infused oil.
Melt the beeswax: Close the jar and return it to the double boiler. Heat gently over very low heat, stirring occasionally, until the beeswax is fully melted and blended with the oil.
Pour and set: Remove from heat and let cool slightly. Pour into a clean jar or tin (about 1/3 cup capacity) and allow the balm to set completely before sealing.