Toothpaste. put a very small amount onto a clean lint free cloth and rub in small concentric circles very lightly for around 1 mins, then use another cloth to gently wipe it away. use this a few times until the scratch has gone.
the abrasiveness of the toothpaste is enough to remove the burrs around the edge of the scratch making it appear less significant. this method is used for things such as motorcycle visors to remove scratches without adding more.
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