Explain what you mean by dulling out?
I'm assuming you mean after painting them you don't want them to look smoked and dull, but instead a polished shiny smoked look to them.
It's really as simple as prepping the surface for paint, doing multiple thin coats of black paint, and plenty of patience wet sanding them so you get a perfect shine to them. A coat of clear never hurts to keep the paint protected after you get the desired look.