About 10 years ago, I set up an electrosys tub to clean some brake parts. I spent some time and had a good commercial variable DC power supply rather than just a battery charger, and experimented with it quite a bit. It worked, but not as well as I would have liked, and it was quite messy. Nowadays, I have a 5 gallon pail of Evaporust, that I just put parts into for a day or two, and the results are much better. I did a complete '50 Ford grille (the chrome was good, but the backs were quite rusted), and was amazed by the results. The drawback is that it is quite expensive (I paid slightly over $100 for the pail with shipping) but 5 gallons is supposed to treat about 150 lbs of parts and I am still using mine. If you have a large piece to do (fender, etc.) electrolsys with a custom "tank" may be the way to go, but IMHO, a bucket of Evaporust gives much better results, and is cleaner, faster, and easier.
I think that a molasses bath works by the same method (chelation), but I've tried that as well and never had good results. I probably had the wrong kind of molasses or the wrong mixture ratio or something. If I ever get a large part I need de-rusted, I may revisit molasses, but for now, the Evaporust is doing fine.