The recent HeroQuest Zombie I did was a Codex Grey basecoat, wash with Devlan Mud, highlight with Rotting Flesh (touch of white added for further definition), glaze shade with Scaly Green & Deep Red ink. If it appeals
I did some GW zombies ages ago with a white undercoat, green ink wash followed by a red ink wash. Because they dry in slightly different areas you get red & green bits as well the overlapping dark bits. Then drybrush with something, Rotting Flesh or Ash Waste Grey or somesuch. They did the trick for a really quick effect that still has some colour Sort of the reverse of Supervike's method.