Ok, that depends what effect you have in mind. I take it you want a tarnished, worn, drity, gold-ish metal.
I happen to have used such a colour on my possessed, that might just do it for you. Here's an example of some of my miniatures to give you an idea:
If this is indeed the colour you want ot achieve (or close to it) let me tell you how I did:
1) Undercoat in CHAOS BLACK
2) Give a heavy drybrushing with TIN BITZ
3) Mix TIN BITZ (20%) with DWARF BRONZE (80%) and apply a lighter drybrushing. I do this because this stupid dwarf bronze is as liquid as milk! And for drybrushing you need "creamy" paint. Tin Bitz will achieve that for you.
4) Add some gold paint to lighten up the mix, or use pure gold paint, depending on the tone you want, and give a VERY LIGHT drybrushing. Careful not to clog the previously created shadow effects! I use the Vallejo "Oro viejo" or something like that. But surely a darker gold from GW would also do the trick.
Try it and let me know how it turned out!
Hope this helps!