Every time I make melt-and-pour products such as balms, butters, or anything containing wax, there is an unavoidable film left in the beaker after pouring up.
Here's a quick and easy way to clean butter or wax-coated beakers and equipment that has always worked well for me.
Return the container to the heat source and gently remelt. While the container is still warm, wipe the excess out with a paper towel.
Remove as much as you can with the paper before proceeding to sink for final clean-up with soap and water. The less residue in the container, the more your drains (and plumber and partner who hates paying plumbing bills) will thank you.