I have used electrolysis before, but didn't have my power supply unit then, so tried it again.
This is a very old Chain block I need to use to lift a planer. It's been up in my loft since the last time I used it 15 years ago. I did two runs on the block, each 24 hours.
I used an old float as one electrode, but had to put some wood in to make it sink
first power up, at 20V, it was maxing out the PSU at 5.5A, but this tapered off over 24hrs to about 0.7A. Second run was similar.
This was the float after two 24hr runs.
Result was very good on the pulley, but as I expected, the chain was more difficult to get consistent contact to the electrode, so some parts of the chain were cleaned, others were still rusty. I tried cleaning the chain manually, but it was endless, so I gave up!
There weren't many parts of the chain which were still rusty, but if I bothered to do it again, I would thread the chain on a long loop of wire. I did have a square of wire mesh in the bottom of the bucket, but you need to get every link to make contact.