Thanks for the input, men. After further reading, online, HCL does well to remove the rust but can also be harsh on iron itself (and removing iron from the steal alloy would definitely cause embrittlement). The reaction produces a liquid solution (no protective layer as with iron phosphate). And it is dangerous to use (but what isn't...). So it looks like everyone is right on this one.
I'll probably still try it, though
Thanks, again.
