Adrian Worman wrote:We use aluminium oxide in our machine for smallish pieces, even shoved the odd wheel rim and head in there, leaves a lovely prepped finish

Yea I have tries ally oxide and it does work very well,but for cost effective approach I use play sand and strain it well, for 25 lbs for 5 bucks it is well worth it and recovery is not as important ,I try to get most of it but it wont hurt it to leave it on the ground,
The soda media works very well too but, I could only find it from a Restaurant cleaning service and they didn't want to sell me any,Harbor freight has it, but not in the local Harbor freight store here I didn't want to wait for shipping,cost and running out and needing more etc.