My best guess without seeing the guitar is the gold is simply wearing off.
It's just a thin plating and since you actually PLAY the guitar
it's going to be subject to wear.
I have cosmo black plating on one of my guitars and it started to show wear within a few months. Cosmo black is known for wearing off quickly though.
Post a pic or two if you can so we can see if it's wear or tarnish. If it's tarnish, go to a jeweler and ask for something gentle to clean gold.
If it's wear, you'll just have to live with it, sorry.
Mic
