NORTHERN EUROPEAN HELMET ZISCHAGGE from the 17 TH Century URGENT NEED HELP !

[Matchlock]

Originally Posted by Cerjak

Thank you Michael I will try.

Well,

I feel like I should have added one important fact, so here it is:

You might as well not do anything about it and just leave the original surface alone. After all, your fine zischagge has come down to you over about three centuries and it is still there - so don't worry: it won't dissolve or even alter while being being with you.
If there is one thing about conservation of virtually 'untouched' surfaces that I have learned over the decades, it is: just leave them the way they are!!!

Best,
Michael