The terms “finish,” “prepolish,” and “polish” are often used interchangeably, and can cause confusion. There are no universally accepted definitions of the distinction between prepolish and polish (what steps fit within each category vary depending on who you talk to), but the one thing that is accepted is that you must work your way through progressively finer abrasives to achieve a highly polished surface.
You’ll need a buffing machine or a flex shaft/rotary tool, plus a separate buff for each kind of prepolishing and polishing compound that you use.
To prepolish, secure a soft cloth buff on the buffing machine or insert a miniature buffing wheel bit in the flex shaft or rotary tool. To charge the buff, hold a stick of prepolishing compound, such as Tripoli, against the spinning buff until the buff has a light coat of compound on its edge. Press your jewelry piece against the charged buff, moving the jewelry piece continuously. Don’t hold your piece against the spinning buff in one place for too long — you could end up wearing away material or creating scratches from the buff, called “drag marks.” Recharge the buff as needed.
Between steps, thoroughly clean your jewelry piece with dish soap and a soft toothbrush. Take care not to cross-contaminate your buffs and compounds; this could result in scratches in your piece and ruined buffs. If your piece is suitable, you could also use an ultrasonic machine to clean it. Rinse and dry the piece.
To polish, charge a fresh buff with polishing compound, such as rouge. Polish your piece with the buff, recharging the buff as needed, until your piece is uniformly shiny and all evidence of pre-polishing has been removed. Clean, rinse, and dry your piece.