One disturbing thing about fakes and reproductions is that they tend to get better as the counterfeiters learn new methods of production and universal methods of detection.Back in 1972, when I received my initial training, some folks thought we should reveal all we knew about counterfeit coins while others insisted we keep everything secret so asnot to help the counterfeiters improve their product. We took the middle ground and revealed just a few of the distinctive defects ("markers") used to identify a fake.

The group that wished us to keep everything secret turned out to be correct. The more we divulged, the more difficult authentication became as commonly seen defects onvirtually all fake coins eventually disappeared. At one Summer Seminar in 1973 or 1974 I showed the class a newly produced $10 Indian and one of the "markers" to use to easilydetect it. Within a short period of time, the identical fakes showed up at the authentication service with that defect removed.

I don't mean to alarm readers, but the counterfeiters have taken huge leaps forward in the last several years so that many of the state-of-the-art fakes would fit undetectedinto a coin collection among the prized pieces.

To read the complete article, see:
Counterfeits get better and better(https://www.numismaticnews.net/article/counterfeits-get-better-and-better)