What coins should you not clean?

Are you wondering which coins you should avoid cleaning? It's a common question among collectors and investors alike. Some coins, especially those with a high value or historical significance, should never be cleaned as it can damage their surface and reduce their worth. For example, ancient coins often have a patina, a layer of discoloration and oxidation that adds to their character and authenticity. Cleaning this off can strip away the coin's history and negatively impact its value. Similarly, coins with original mint luster, a shiny surface from when they were first struck, should also be left untouched as cleaning can dull this feature. It's important to be cautious when handling and caring for your coins, and to seek the advice of experts if you're unsure about how to properly clean or maintain them. In general, it's best to err on the side of caution and avoid cleaning coins unless absolutely necessary. So, if you're asking yourself 'What coins should you not clean?', the answer is: any coins with historical significance, original mint luster, or a patina that you want to preserve.