I set up the electrolysis tank method today and "derusted" the receiver per Dan Wildhaber's suggestion. Things went well enough. I changed the generic Youtube set up only in that I used a rectangular bucket, since receivers are rectangular, and pointed the four basic flat sides toward the four corner anodes when I suspended the receiver in solution. 8 hrs of electrolysis removed all the rust. I now have the rotary bolt freed up enough to drift to and fro a 32nd or so, but the trip remains stuck fast. I soaked the works in penetrating oil for the night.