Once your coin has been authenticated and graded, it's ready to be put up for auction. 'Collectors want their coins 'original,' which means they don't have any surface impairments and show no signs of cleaning or damage,' he explains. While many beginners tend to believe that a coin is worth more if it's brighter and shinier, the opposite is true for most coins, McCartney says. 'A coin is generally going to be more valuable if it's higher grade,' McCartney says.Īnd take note: Experts advise against cleaning any coins you believe may be rare and want to sell. A grading of one means the coin is worn to the point of barely being recognizable, while a 70 means the coin is nearly perfect and looks like it was just created.

Serious collectors want all of their coins to be authenticated and graded by a third party that has certified their value, McCartney says.Ĭoins are typically graded on a scale of one to 70. You should also send your coin to a rare coin authentication and grading company, such as Numismatic Guaranty Company or Professional Coin Grading Service, to be independently evaluated. 'In general, the internet has a lot of misinformation about coin prices,' he says.

If you're lucky enough to find this rare penny or have another coin you think may be valuable, start by contacting a reputable coin dealer or auction firm rather than relying solely on information found on Google, McCartney says.