Smoke firing
Dad starts off in the electric kiln and then smokes in an old bin with interesting wood clippings. the pots are cool and the wood fire is completely separate. If you take pots out of an electric kiln too early, when the kiln is hot, you can ruin the elements.
Burnishing
Some people use oil to cover the pots, let it slip in and then burnish
Some people start the process of burnishing off on the wheel.
dad uses a sone and a metal tool. Finishing off with plastic. He does not use terra sigillata
If you are going to burnish a slip with a colourant in it the colourant needs to be less than 10% of the mix.