How Do You Treat "Milk Spots" ("Water Spots") In Grading? (2004 LMC)

I am no pro but I consider milk spot or spots of any kind to be part of the eye appeal. IMHO they reduce the eye appeal. I consider grade as a technical thing,the strong-ness of the strike. MS60 being less strong of a strike then a MS70.I don't know if the professional graders add or subtract eye appeal before the final grade.
John1

Nothing you can do about them.

The milk spot, most commonly found on TPG'ed ASE, often did occur because of the type of slab that was used by both NGC and PCGS, although they no longer use that encapsulating method.

The technical grade is very precise. For uncirculated coins the most influential part of determining the grade is the number of marks, bag marks, or other hits to the surface of the coin and it's rim. For circulated coins, the amount of wear from handling is the key to determining a numeric grade.

Either of those two areas of grading may be affected by problems that cause them to be labeled "details" coins. Or coins that have a significant enough problem or problems to eliminate them from a numeric grade. Most commonly cleaning, bad rim dings, larger scratches, any type of reworking such as hole filling or metal movement and a number of other problems would cause a coin to be listed as details. So instead of it receiving a VF-25 grade, as an example, it might be holderd as VF, Details, Environmental Damage.

In the case of carbon spots, which is a form of degradation from oxidation, rather from chemical changes found to produce the milk spots, you can have top surface spots that do not do damage (or very limited damage) to the surface below, all the way to corrosion which does affect the coins surface and is considered environmental damage.

For very minor carbon spots that do not cause a details grade, those spots will most certainly be considered as negative for eye appeal by almost everyone.

Above all, remember that the grade of a coin, even if slabbed by NGC or PCGS DOES NOT indicate the value of the coin. Just look at Heritage, which has the best kept records on sales of TPG'ed coins, and you will see instances of the "same" coin in the same TPG holdered near the same time that sell for hugely different prices.

In other words, a 1909-S VDB cent might sell for 300% more or less than another example just because of a couple of those carbon spots, even though PCGS or NGC graded them both at MS-63 RB the eye appeal will make so much of a difference that its silly to think there is a price guide that will cover all those variables.

Thanks, Pete, most interesting. The use of the apparent misnomer "carbon spots" is so ingrained in the hobby that I doubt it could ever be replaced by a more correct term.

I do and he's partially correct. The carbon spots on Lincolns are indeed mostly carbon based. I've looked at them on an electron microscope years ago but I forgot the exact composition....as I recall there were some other trace elements.

The author's idea of putting a sulfur containing material (rubberband) and a carbon material in contact with a copper coin is plain old dumb. The carbon spots typically on Lincolns are due to a Mint process and the more volatile components have long evaporated away forming a very strongly bonded carbon-based material behind. The spots SHOULD be referred to as "carbon spots" because carbon is the primary component. They cannot be removed by chemical means without permanently damaging the coin.

If you have a nice, carbon spotted Lincoln you don't mind ruining....try this, I've done it. Hold it under a torch and the spots will vaporize pretty rapidly. Further proof the spots are mainly carbon based.

BadThad,so, a carbon spot can happen on any coin correct?
Milk spots happen during the minting and can appear latter. Is this only to newer coins from the U.S. Mint?

I do hope you will suddenly remember where you read that! Let us know if you do!

Just knowing that the information might be out there means I will start looking for it! Thanks!