“Mint” does not mean “shiny.” Read that again! The description “mint” only applies to a knife when it remains exactly as it came from the factory.  It can not have any use, or wear, period, although, poor finishing and manufacturing defects which were present when the knife was produced do not disqualify it from being mint. Once a knife is no longer mint it can never be mint again.  A knife cannot be “cleaned to mint.” See; Cleaned.