I had a rusty old oil pan and made one of those electrolysis deals and it work well.
. I put the part in for 48 hours and then cleaned it with a scotch brit. All the rust, grease, paint, and dirt were lose after it had set for the 48 hours and cleaned up easy with hot water and soap plus dried with compressed air. I used a DC variable power supply set at 12 volts
steve
steve