My knowledge is limited here, but I've seen it done. You'll need a tumbler, ceramic media (there are several different sizes and shapes), some water, and I believe it is also common practice to add some type of liquid detergent. Then you just place your blade or parts in the tub of the tumbler and let it tumble. The ceramic media creates the finish on your parts as it vibrates or "tumbles" the the parts and media around the tub. The water and detergents cleans the surface as the media scrapes and vibrates around the parts.
A more knowledgeable person will come around soon and give a more enlightfull answer I'm sure.