Drano, who's major ingredient is lye, does not harm steel. That's why you can pour it down a drain. It dissolves organic materials, which is why you shouldn't get it on your skin. It may corrode aluminum, I'm not sure tho. Ammonia will corrode non ferrous metals.I don't know about that, but I imagine that it would be really hard on the steel, possibly causing major damage.
Brownell's sell a chemical nickel stripper.