My suggestion: Set this up and try it out. Pick out a rusty relic for the experiment, use baking soda if you don't have the washing soda, you don't really need a lot of current IMO at least for something small. Good coverage is line of sight, or something that goes all the way around is a good idea. Once you start using this, you'll wonder why you had never tried it. It sounds like the embritlement issue is only a temporary state, maybe someone can add some more info on that. But there are a hell of a lot of items where that is not an issue.
