removing the rust and paint
The lat poster was absolutely correct.
We used a urea plastic bead for all filler and paint removal on all surfaces...........including some wodden architectural pieces! We used 60 grit "aluminum oxide for rust removal and to prep industrial weldments and castings for finishes. We never warped a panel on a vehicle, though there was a rolls that came through that had two types of aluminum panels and one did get pitted quite severely, even at lox pressure and with the plastic.
As far as the rust removal, the aluminum oxide has been their choice of material because the particles keep a "sharp edge longer, and that means the work goes faster, and as it is swept up, sucked through a screening system and reused ..........it's more economical.