That is only one way. Toning is simply the darkening or coloration on a coin caused by contact with any reactant. The chemical reaction can occur as a result of contact with hands, liquids, air or other coins. Some patterns are so distinct they can be identified and named, - ie album toning, roll end toning and bag toning. Some are considered pretty enough to command a premium. Which prompts counterfeiters to create artificial toning.
Pictures of toning can be found here.
https://goccf.com/t/53247
Pictures of toning can be found here.
https://goccf.com/t/53247


















