And how do you propose to know how blue-tinted those balls are without being able to tell what they're reflecting and what the camera's white balance is set to?

I blurred the image and took a few colour samples; the balls are grey in the image, with very slightly more red in them than green or blue. That doesn't mean they're actually grey; they could be slightly blue and reflecting a slightly red scene or vice versa. They could be slightly green but the camera settings have "corrected" it to look grey.

How can you tell that the "dull" ones are oxidised, as opposed to roughened, blurred due to movement or covered with some other substance like lubricant?