Here are my orcs with their skin painted. The AD&D Monster Manual describes their skin as either brown or brown-green with a blue sheen. I wasn't in the mood for mixing paint, so I went with brown straight up. But at least they're still not green. And it will add to the diversity of color in my selection of baddies- orange gobbos, brown orcs, ochre bugbears, gray hobgoblins etc.
By the way, I like the sculpt of the three regular orcs here; they're more recent (Reaper) sculpts, but they still have a lot of old-school spirit about them. The big guy is pretty frickin' sweet, too.