Q-Tips + rubbing alcohol + patience
I couldn't get everything out of his chest cavity, but I figure it's the least offensive bit o' blue (it's like he's got a spark

), and if I do blackwash it, that'll all get covered up anyway.
oh I also didn't try to get the two tiny blue bits on his face, since I would have obliterated the rest of the paint as well. But the two blue helmet nubbins are gone.
I'm really liking his chicken legs. To be honest, it makes me realize just how impractical man-legs would be on a big heavy robot.