This page explains the use of machinable wax in machining and provides instructions/information on its technicalities.
Machinable wax is used to secure parts during part flips. It is a replacement for Bondo, thin webs, soft jaws, or tabs. It is incredibly convenient. This wax is called Rigidax (24-12 blue), and can be found on machinablewax.com.
To use the wax, machine the first side of your part, then clean it thoroughly with soap and water, making sure to get rid of any leftover oil. Heat up the Rigidax to 275 F and wait for it to melt. Once it's melted, stir it for about 5-10 seconds with a popsicle stick, for example, and then pour it into your machining cavity. Let it sit for at least an hour, waiting for it to cool and harden. When you do your part flip, the wax should hold your part in place as if it were still in the metal, although it's not quite as rigid.
To melt your part out of the wax, heat up mineral oil or Bioact 280 to 180-200 F (here's the documentation for Bioact 280). To get the part out of the stock initially, you will probably have to shove it out with a stirring rod or something to that effect once the wax has been softened. Only after the part has been isolated from the stock will it be able to shed its wax. It helps to stir the part around or to scrub it with a toothbrush (this is faster).