Burnishing greenware pieces takes a lot of time and patience. I use a metallic, plastic or wooden object, or even better a polished stone such as an agata or hematite.
Burnishing is easiest when the clay is wet slightly with a lubricant such as vegetable oil.
When the piece has dried I fire it in my kiln at around 900 degrees (or at 980 degrees if it will be glazed inside later on – see below). When the piece has been fired I apply wax and polish it.
There is one very important point to keep in mind: burnished pottery should not be used for food or drink. However it is possible to apply glaze to the inside of e.g. a vase and fire it again (at 1,000 degrees) to make it waterproof.