Burnishing pottery is a way of creating a lovely smooth, warm, skin-like surface on your pots without using a pottery glaze. 

Burnished Pottery – “Large Seed Form“, by Pat Joyce (CC BY-NC 2.0)

It involves rubbing the surface of your greenware with a small hard object like a burnishing stone. The rubbing action compresses the clay particles on the surface of the pottery and creates a smooth finish. 

Clay can be burnished when it is stiff leather hard or bone dry.  You can use almost any object that is hard and very smooth to burnish your pots.  The object needs to be smooth because if you have any small dents or bumps in your burnishing ‘stone’, this will scratch the surface of your pot.

Some of the items potters use to burnish are smooth pebbles, large marbles, or the back of a metal spoon. 

You can experiment with the rubbing action that feels best for you.  It can be circular or back and forth, just as long as you cover the whole pot. 

Burnishing Bone Dry Clay

The advantage of burnishing bone dry clay is that you can sand it lightly before you start burnishing.  If you want to know more about sanding pottery go to thePotteryWheel.com at the following link - pottery sanding techniques.

However, if you are going on to burnish bone dry clay you will need to add a little moisture to the pot.  Adding moisture will enable the clay particles to compress down, rather than crumble when you burnish.

You can add moisture by adding a little water or oil to the surface of the dry clay.  You can use different types of oil, including vegetable, mineral, and baby oil when burnishing. 

It’s best to add the water or oil a small section at a time as you burnish.  If you cover the entire pot with moisture, by the time you work your way around the clay will have dried out again, and you will need to add more. 

Burnishing is a time-consuming way of decorating pottery, but the effort involved pays off in how extraordinary the finished result can be.

Reference -  thepotterywheel.com -