Toning question

Cleaning is not an automatic fault with third-party grading services. There is "market-acceptable" cleaning which is considered within normal boundaries for a particular issue, and then there is more recent, harsh, or UNacceptable cleaning which is considered a problem.

 

Not just how, but often when, as well. If a cleaning was not abrasive enough to leave marks on a coin, and that coin's surface is then given a generation or century or more to react to the environment, it generally becomes a bit more acceptable.

 

John, fully 80% of all older coins have been dipped. And yes that is a realistic number. And millions upon millions of them are in cleanly graded slabs. NGC and PCGS both dip coins themselves, and then slab and grade them. And they have both done this basically since they opened their doors for business. But it has only been since 2007 that they began advertising to do it for you.

Dipping coins to remove toning is and always has been completely acceptable in the numismatic community. And dipping has been quite common for centuries, not just a few years. It was invented in Europe long before the US even existed.

Now I think most folks are aware that the TPGs have been dipping coins since 2007, but far fewer of them are aware that they were doing it long before that as well as I stated above. The oldest known published confirmation of this were articles in Numismatic News and Coin World back in 1995. See below for a reference.

PCGS and NGC Dipping Coins

The Professional Coin Grading Service and the Numismatic Guaranty Corporation
have confirmed that they have been dipping coins upon request. The coins are
not marked on the slab as cleaned.

References: Numismatic News, 8 Aug 1995, p. 1; Coin World, 18 Sep 1995,
p. 1, 7.