Discoloration of gold

Hi folks, I’m sure this topic has been covered here in the past and
I did search the archives. I found a lot of about Prips
flux and Saving solution but none which addressed removing
discoloration on gold. My 14k piece has a reddish hue to it that
seems difficult to remove. I think I probably overheated it and
caused the discoloration. Is this the gold equivalent of fire scale?
Does anyone have any suggestions on how to remove it? I would
appreciate suggestions.

Thank, Jenn Mank

I have had some success removing this type of stain with diluted
nitric acid @10%. Nitric disolves copper so be careful. Observe
safety protocols when working with any acids.