/diy/ - Do It Yourself

I tried asking /g/ but got directed here.

I got a 3,5 to 6,3 mm jack converter that's plated with gold. However, it's matte now as opposed to shiny when I got it like 4 years ago. I'd like to make it shiny again.

I had sort of the same problem with a copper bracelet which I fixed with a non-concentrated solution of acetic acid (the type you use to clean your sink and kettle to remove chalk), but I'm not sure this can work on gold, since the converter will be used for electric current.

Any ideas?

Pic related.