I’ve been using Evaporust to clean up small parts for a couple of months now, but it gets pretty expensive in large quantities; a gallon is about $20 via Amazon. I just soaked a window scissor mechanism in a tub for two days and got it pretty clean, but a gallon was barely enough to cover the metal. Electrolysis is a great way to remove rust at scale, and all it requires is a tank of water, some salt, and a hunk of sacrificial steel. This video compares the two methods in detail, and finds that they both work about as well as each other. All things considered, I think I’d rather spend $20 on a rubbermaid tub and some salt.