Put all of the ingredients (except for the peppermint oil, that will go in last) in a double boiler or oven safe bowl
Melt the ingredients and mix together. If you don't have a double boiler, you can place a glass oven safe bowl over a pan of simmering water or simply use your microwave - just be sure to microwave for 30-60 seconds at a time, take the bowl out and stir, then microwave/stir some more until everything is melted
Once your base is melted and mixed, remove from heat and add 10-20 drops of peppermint oil (or other oil of your choice! Sweet almond oil, orange blossom, lavender, lime, coconut, and vanilla are all great options. Just be sure to use a fragrance/extract that is cosmetic grade and safe for lips!)
Line up your lip balm tubes or tins and using a pipette, transfer the lip balm base to the containers filling right below the top edge
Once the base has cooled, take the pipette and top off the container to cover any sunken in areas that have settled (this happens especially on lip balm tubes)
Let them cool for a few hours until they are firm and that's it!