The bead above is one I made that I buffed to a nice moderate shine with a combination of sanding, more sanding and a lot of rubbing on jeans. I later went on and used a dremel to bring it up to a high shine.
Finishing techniques for clay work are some of the most frequently asked clay questions I get so I went and looked to see what the awesome Desiree McCrorey had written on the subject and it turns out she has TONS of material. I’m linking to her pages specifically on machine buffing since it gets you the most eye popping wow without varnishes.
I have a little bench grinder very similar to the one in her tutorial – it’s a no name brand from a discount tool store – and it was approximately $40. It works like a dream. I usually sit on the carpeted floor and buff there so that the flung objects don’t go far but if you mount yours to a table, do follow the safety advice she gives… you WILL fling objects and sometimes I fling small bowls and vessels.