I suppose that in some cases someone could try to pass off a clean chip as "unused" but I would think the downside would be that the grime/junk could do something to the condition of the chip. Or am I off-base?

To me, the clean chip looks "better" and I don't get the willies when handling it. Or when showing it off to others (they like to touch, too). Like you said, we all have our preferences. I'd be curious to know more on the "don't clean" position.

Thanks.