I always thought it to be
"unused or appearing to be newly made and never used: a book in mint condition."
as defined by dictionary.com.
How is it that a camera with "less than 1k shutter count" be considered mint? Or when something is "mint condition, with the exception of some scratches"? Or worse still, now there seems to be a new category: "minty" condition. WTH?
Something is either in mint condition, or it is not. Almost mint is not mint, nor is it "minty". There is no such thing! Please stop abusing words and distorting their meanings to mislead people.
(Now where's my packet of Fisherman's Friend?)