Coin doctoring. Detectable?

Dimetime

What can you guys tell me on identifying dipped coins. Silver is my concern as copper you can tell pretty easy. I've seen dips for sale claiming "impossible to tell". I don't want to buy a coin and have it deteriorate later. If a coin is dipped, will it over time tarnish or change from a natural state? What's the best way to detect dipped coins? Do they deteriorate later?
Thanks for your insight.

KoinKollector

Owning a dipped coin isnt a problem. Dipping isnt "cleaning". The problem comes when the coin is imporperly dipped. Either over-dipped or not correctly rinsed. If you overdip a coin you basically just strip away the luster, silver will have that dull grey, dead, look to it.

nwcs

Diluted and carefully rinsed dips are usually very hard to tell without a microscope. You can tell when a coin has been excessively dipped or repeatedly dipped by the luster. If there is no luster, but the coin is white, then it was way over dipped. If it is an uncirculated coin that is bland white (like a fluorescent white) with little luster with a light pitting on the surface it is dipped.

If a dipped coin is not properly rinsed, the coin will definitely begin to tarnish pretty ugly and be body bagged by the services. If a coin is very carefully dipped and rinsed and stored in a holder like an intercept shield, it should last a long time. But badly dipped coins, even in certified holders, can turn ugly within a few months to a few years.

Dimetime

Intercept holders won't prevent the coin from tarnishing? I collect Mercury's and have moved my purchases to more lightly toned, original looking rather than the 75 year old "blast white" coins. I just don't want to find my collection in ruins later by coins dipped that I couldn't tell. How is PCGS at catching these?

Mark

Dimetime:

I do not know how good PCGS is overall at catching over-dipped coins. But I have purchased a couple of blast white PCGS coins that have turned a bit after I purchased them. I presume this outcome was the result of improper rinsing of dip. As a result, I prefer to buy silver coins that I know have been in holders for a few months, either because I have tracked the coin on a dealer's website for a few months or because the coin is an older style holder.

Mark

Fairlaneman

Dimetime:

Now you are on the right track. Buy the Lightly toned coins and forget about the blast white dipped coins. Of course, from my experience, your lightly toned coins will grade lower because some grading services are just in love with blast white dipped coins. Examples can be shown if need be.

Ken

nwcs

Intercepts are a good way to help reduce corrosion potential, but it is not foolproof. And it has to be replaced every 10 years. I'd say that PCGS is OK at catching badly dipped coins, but sometimes a dipped coin can look just fine but because it wasn't rinsed well it will continue to eat the coin surface. Nothing you can do will stop it.

There's no good way to go that's foolproof. AT doesn't have to be wild and crazy colors. It can also be a dipped coin that was left under a low power magnifying glass to re-add tone. To me, the best way to be sure is to learn a lot about the coin series and have a very discerning eye. In most regular coins, the flow lines (which create the luster effect) are evident at 16x and 20x. PL coins are an exception, of course, and also are less prone to problems from dipping. Also be careful of artificial frosting.

Neil

clackamas

There are many original 75 year old coins that are blast white and have never been dipped. For my money make it blast white. Let me be the one to neglect it and make it tone.

To answer the question: Look for stains around the devices. Especially where they meet the field. Look for luster or lack of it. Look for wear. A diped may be well done and not detectable but on an AU coin? An AU coin from any year should have some toning. Many Morgans are completely orignal Blast white. They hid in bags for 100 years and were sold directly to collectors who took care of them, especially the early CC's. Bust coinage should have some toning. Seated coins as well, except for the 1860-O seated dollar. A hoard was found at the mint and relased in the 1960's so many of these are legit blast white.