The problems with the acid removers is they activate the surface so you need to be ready to apply another finish or to passivate the steel immediately afterward. The Steel White mentioned earlier is pH neutral. Another producti I'd never heard of came up in another forum described as follows:
"Put some Evaporust at the top of that list. It's a non-acidic, biodegradable, non-toxic liquid that looks like weak antifreeze. You soak rusty parts in (it) for 2 hours or 2 weeks, and they come out rust-free and otherwise unchanged. Hard steel with carbon content comes out looking black. Great stuff. I've used it on machine tools that looked hopeless, and everything from taps to gun barrels to brake rotors.
"It's available online, runs $20 or so per gallon. It's re-usable until it stops working, then you pour it down the drain."
If you can't buy this chemical where you are, you can request an MSDS sheet from the company and the raw ingredients will be apparent from that.
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