I've never had that happen with metal needles, even though I have some old ones where the color has faded off the tips, it's never gone onto my yarn or project. Just the opposite in fact, I did a shawl with a turquoisey yarn and my bamboo needles got a little bluish.
Yes, you can put the stitches on some scrap yarn and try washing it; even just washing by hand with a little soap or detergent should help somewhat. Then see what it looks like after it dries.
sue- knitting heretic