Conversely, for anything dark like that, I would wash it with a thicker mix of straight black, just to make sure I got all the shadows taken care of, giving it a good wipe at the end.
Actually, when I do gun barrels, I paint the whole thing black to begin with and then drybrush with metallic gray to get a "gunmetal" look, after which I don't bother washing it at all.
Works for me!
![Big Smile [:D]](/FSM/CS/emoticons/icon_smile_big.gif)