1: Paint or spray the whole badge flat black leave until completely dry
2: Take a gold or brass metallic paint and soak a paint brush with it, thoroughly wipe of the gold leaving a dry brush and then lightly brush over the whole thing excluding the non raised parts. The technique is used frequently in prop design and minatures dry brushing
3: Seal with a varnish or clear coat lacquer and enjoy :) *IMPORTANT* This has been updated recently as I was sent photos of an apparent screen used prop by a friend in the industry. There is accurate beveling, sloping and font used for Dredd.