Machinable wax is very useful for testing new prototypes before machining the designs from more expensive materials.
Below is a video of a DIY CNC machine ( Shapeoko ) cutting wax.
Machinable wax usually comes in blue blocks or cylinders that look like these and is a bit expensive.
Luckily it’s not that hard to make your own machinable wax at home and you can save heaps of money because it’s also reusable.
To make your own wax all you will need is Paraffin wax and old plastic shopping bags. (4 parts wax for 1 part plastic)
For more details, have a look at this link. http://www.instructables.com/id/Machinable-Wax/