I have been using polishing wheel so far (just got to be carefull odd shape parts dont grab) but heaps cheaper to set up a polishing wheel with a $50. Six inch grinder, a rag wheel and some polishing compound.
I used to do it this way years ago. VERY time consuming. These days, if you use the right media you simply wash the dirt off them and then place them in the tumbler for four - six hours and it is all done for you.
