So I said I'd never paint these, but never say never...
A golden "golden penis" and a whole lot of gold doubloons!
Shading was initially gryphon sepia and then another mix with leviathan purple and sepia in selected recesses. Then a final selective shade with Agrax.
There is one more possible option left as well:
Adding some minor tarnishing with a thin Hawk Turqouize, Skull White and Dark Angels Green combination in a few patches. Not too sure though because gold doesn't oxidise light bronze... Goes more brown I think as it ages.
Love to hear your thoughts about whether you think they're needed.