Place the tallow, beeswax, coconut oil, and shea butter in a double boiler over low heat.
Allow everything to melt slowly, stirring occasionally. Once fully melted, remove from heat.
Whisk together the arrowroot powder and bentonite clay in a small bowl.
Stir the powders into the melted oils, mixing thoroughly so there are no clumps.
Allow the mixture to cool slightly. Add essential oils if using and stir again.
Pour the mixture into containers and allow it to set completely at room temperature. As it cools, the deodorant will firm into a smooth balm.