I really like these models, and they are very in character for any Ork army.
I start off with a black undercoat and then do all the metallic bitz with a drybrush of tin bitz and chainmail.
I then do all the Ork skin with a dark green, highlight with Goblin Green before doing final highlights with a mixture of Goblin Green and Bleached Bone.
The orks' teeth are first done in Bleached Bone before
final highlights of Skull White.
Uniforms (and I say that in the broadest possible sense with orks) are usually Codex Grey with highlights in a lighter grey.
Bases to fit in with the snow based theme and Cityfight games are done in Codex Grey before drybrushing with Skull White.
These are partially finished Burnaboyz in a game (gasp unpainted miniatures).