I draw shiny metal colors differently. I use a layer of the flat color of the metal (or whatever it is) and then 3 layers on top of that, one with a darker color than the base color, another with just black, and then another using either white or the base color using a Glow or Soft Glow blending layer. I can then add more highlights (like colors from light reflections) on top of that and get real fancy with it.
Here's some examples
It has a more graphic feel rather than realistic but it gets the message across.