I've used ATF, mostly because I was given several gallons of old Dexron II and Mercon that is no longer used in newer vehicles.
Thanks Keith. I've had good results with ATF as well.
also find that WD-40 with 0000 steel wool works very well to remove loose rust or to clean Damascus that has such deep patina that the pattern is obscured.
I've used 0000 with Kroil, or Frontier Pad and Kroil for this purpose. Target and Wal-mart have three packs of the same scouring product as Frontier Pad, but for much less money than buying them online.