DaN\'s right.
I\'d go with a bronze color and then shining gold drybrushed over it.
if you want a shinier metal, do it in straight shining gold, then hit it with burnished, and maybe even hit the corners with a spot or two of mithril silver.
go over this with a wash...
flesh wash for an older look, brown ink for a darker one, and chestnut ink for a richer look.
when using the metallics and not drybrushing, you\'ll need to water them down, as they can get clumpy.
furthermore, water down the inks a good 1:1 water to ink ratio, at least. you can go over it again once it\'s dry if it\'s not enough color.
once you get the whole thing of base-color, then color over, then highlights, you can easily do NMM gold, as it\'s not too hard (just layer from snakebite leather to skull white through the yellow-browns).
Good luck, and cheers!