Nickel tarnish...?

[Khukri]

My M1843-1863 Belgian OR 2nd Cuirassier Regiment:
-I don't want to take the helmet apart. So it will not be simple to wipe the nickled shell.
-I read: vinegar.
But: the main problem might be not only the nickel layer itself becoming dull...but the oxidising of the substrate layer...

 

[Tony without Kaiser]

Vinegar will brighten brass so you would have to be very careful. Looks like a beautiful helmet.

 

[Khukri]

Vinegar will brighten brass so you would have to be very careful. Looks like a beautiful helmet.

Thank you for warning me!