Combine coconut and olive oils in a glass measuring cup, and microwave in 30-second intervals until melted.
Add the dried calendula petals and lavender buds.
Let stand for 30–60 minutes then strain. (Warm again if it's too thick to strain.)
Place the infused oil back into the measuring cup, and add the beeswax and shea butter. Heat in the microwave for 1–2 minutes, stirring frequently. (If you're worried about breaking down the beneficial properties in the herbs, place the measuring cup in a saucepan filled 1/3 of the way with water, and heat on low until the beeswax and shea butter are melted.)
Remove from heat, and add the lavender essential oil (if using).
Pour the mixture into a heat-proof glass container and let cool completely.
Will keep for several months. Use as often as needed.