Why you should not clean coins that are old

You probably have seen videos and other sites on how to clean your coins make the circulated look like an uncirculated coin. 

source of this picture:https://imgur.com/t/silverbugs/BRDHNio

You should not never ever clean coins that are over circulated pro-coin collectors like me never do that and you never do that on silver and gold coins as it will remove some metal and it will probably remove or scratch the beautiful imprints on them. in case if you were wondering this method was to remove sticky substance out of coins that are mostly formed with the contact of PVC plastic for a long time. soon I will be making another blog about PVC plastic damage to coins and another on to how to make modern coins clean.

Source of this image:https://i.imgur.com/Q2RuQD9.jpg