Balinese keris bilah color

[Anthony G.]

Hi

I got this Balinese keris months ago and it looks like this 'green'. I can said that I itchy hand and test something on it and eventually the bilah turns metal (silver) color.

Can vinegar brings back the original color form? I try to use artificial vinegar but it does not works that well. Maybe I do the wrong way.

Also, I cannot find any answers on the net. Any idea why some Balinese keris bilah color are black and some are this color of mine?

Thanks