2 a: not spoiled, corrupted, or polluted (as by civilization) : pure b: fresh and clean as or as if new

I would also go for a newer, sharper, and more visually appealing chip, but cleaning a chip does not make it pristine. Pristine is untouched. If a chip is used, it can't be pristine. Too many of the cleaned chips I see are obviously cleaned, and appear worn and unnatural. I tend to follow the rules on coins, if it's Uncirc or Proof and has a little soil, you might lightly clean it. Do not clean a used coin as it will always look like a cleaned coin.

An uncleaned chip can always be cleaned if you decide to do so, and you can control the method. If it's been cleaned by someone else, you don't know how.