I'll make the pitch for electrolysis. You most likely already have the components around the house and garage. You can find the "chemical" component already residing in your pantry or refrigerator. Or, remove rust, oil, grease, AND paint by using a sodium hydroxide (lye) solution. The lye eats the paint off, and the electrolysis steals the paint.
I have de-rusted many a part this way and will work as long as you can fit the part into the non-conductive container. My favorite success story was my radiator shutters for a 1944 B John Deere that were very rusted. The shutters work just like venetian blinds to help heat up the engine temp so that you can switch from gasoline to distillate fuel faster.
After a month of soaking with penetrating oil, no success. At my wits end and about to just throw them in the heap, I ran across this process. I dumped them in and in 3 hours, I pulled them out and was able to operate the shutters by hand! i couldn't even start to twist them with pliers before. Again, you can reuse the solution as many times as you want.
