Having harvested honey 2X this year I've collected enough wax to give candle making a go. There are more than a few things one must know to get this right so I will share what I gathered in data and experience.
First, never melt wax with an open flame. The wax and it's vapor are super flammable. Second, use stuff that you 'donate' to wax cleaning/candle making and use for nothing else. A double boiler is needed.
The main issue with wax cleaning is the stuff that's not wax that is in the wax. I can not imagine what the stuff is. As you can see from the pic it is an unidentifiable muck and you want it out.
So here's how. . .
In a glass or stainless pot (not a double boiler here) collect wax and fill with water. Turn non-flame heat on high until the two ingredients are indistinguishable from one another. Turn heat off and let cool completely. Pour off the water when cool and with a knife scrape off the non wax which is now stuck to the bottom of your wax disc that has hardened again. Repeat a couple of times.
To get the remaining muck from the wax put wax only (and the muck stuck to it) in a double boiler. Heat until completely melted. Pour mix through cheese cloth. Muck will stick to the cloth, wax will move through it. This too may take a couple of passes.
It's messy, time consuming, and it can even be dangerous. But if you have a hive and want wax for cosmetics and candles one has to reckon with cleaning bee wax. The one candle I made was so awful I did not bother to post it's pic. I can see now that I needed one more pass, there was enough muck unfiltered to mess it up.