The Brownells cold nickel strip works well.
Don't know if they still sell it.
It comes (came) in 2 separate bottles that were mixed together along with a prescribed amt of distilled water. The whole thing made about 5qts of 'stripper soln'.
You simply put the cleaned parts into it and left them for a few hrs. The stuff was reusable.
It does eventually deplete itself and then it's disposed of. I imagine there's some special disposal method for it now with all the EPA regs around.
It has a strong ammonia smell to it. MSDS says it a chemical called
ETHYLENE DIAMINE ,,way beyond anything I can figure out what it is and how it works.
The nickel strip soln stuff I have in my own shop was gifted to me by an other gunsmith I used to do work for.
I have an idea it's probably the same stuff and something that 'smith mixed up himself as he fancied himself as a chemist. He mixed his own blueing salts and things like that.
That nickle stripper is black as tar, but water thin. It just sits in a couple glass jars with metal screw caps and has been like that for 40 yrs or so.
Same ammonia smell.
Wire up the plated piece and let it sit in the stuff for a while.
Unlike the Brownells stripper that says it's soln will work in about 1 to 4 hrs,,this stuff I have may take a couple days to completely strip a part.
The plated part comes out with a jet black shiney coating on it that rubs right off with a touch of the finger. The bare steel is obvious underneath it.
I rinse the part and that's it. All done.
The stuff I have will strip nickel, chrome, gold and silver.
The Brownells will not strip the other metals from my experience using it in other shops I've worked in. Maybe they just didn't leave it in long enough,,always in a hurry.
I just used the mystery soln I have to strip chrome from an old single shot Savage .22 bolt assembly. Took about 4 days to work but took it down clean and the stuff never etches or damages the base steel.
Don't know what's in it,,still have my finger tips in tact from handling it.