Toning coins with cardboard

I'm well aware of all of that. I was trying to put things into simple terms that the average layman could relate to and understand.

 

This is what PCGS said when the sniffer was announced - the bold font is my doing.


"......Implementation of the PCGS Coin Sniffer for inorganic materials is planned for early 2011," he told attendees at the PCGS Set RegistrySM awards luncheon at the American Numismatic Association World's Fair of Money in Boston on August 13, 2010.

The PCGS Coin Sniffer uses dispersive X-ray spectrometry (EDX), Fournier Transform Infra-Red Spectral analysis (FT-IR), Raman Spectroscopy and other analytical techniques to detect the kinds of materials applied by so-called "coin doctors" ........"

"Willis explained that some coin doctors use metals to build up certain areas on a coin's surface, for example, attempting to create a full head on a Standing Liberty quarter, full split bands on a Winged Liberty/Mercury dime or improving diagnostic high areas. Metallic solutions such as solder, indium, Clorox®, iodine and potassium or potash have been applied to alter a coin's surface.

Beginning next year, the PCGS Coin Sniffer will use EDX technology to analyze elements of coins on the atomic level. The FT-IR technology that will be implemented this fall analyzes coins on the molecular level. In the EDX process, a high-energy beam of electrons is focused on a coin's surface. Resultant dispersed energy is measured and the atomic structure is determined.

"It's similar to scanning with an electron microscope," said Willis. "Foreign metals as well as metal fatigue due to high heat from a blow torch or laser can be detected." ..........."

You can read it all here - http://www.pcgs.com/News/Pcgs-Coin-Sniffertrade-Uses-Advanced-Technology-To-Detect-Doctored-Coins


So yes, according to them at least, the sniffer can detect metals that have added to the coin.

 

Yes, putty was one of the biggies. This is largely because putty, when freshly applied to gold coins, is at the best very difficult to see, even for some of the best. And it has fooled the graders at the TPGs many, many times.

But putty is far from being the only thing that the sniffer can detect, in fact does detect. About the only thing it can't do is distinguish AT from NT. It can easily detect that the toning is there, it just can't tell AT from NT. But then that's because they are the same.

 

When it's fresh, or even fairly new, it does. Now with time, over a few years, the putty dries out and it becomes a whole lot easier to see, at least for those who know what they are looking at. And that is exactly how and why the puttied coins get discovered resulting in the TPG having to honor their guarantees and then purchase the coin to get it off the market. The TPGs have spent millions buying back puttied gold coins that they could not detect when they graded them.