A Discussion about Surfaces - Part 2 of 2

by Jason Poe

Last week, we discussed original surfaces and how they should appear (in the thread here: https://www.cointalk.com/threads/a-discussion-about-surfaces-part-1-of-2.256003/ ). Let's take a look this week at altered surfaces, and some of the many ways they can look. For more information, take a look at my book.

After examining original surfaces, we can begin to discuss some of the most common problems which afflict coins. Remember, looking at original and problem free surfaces and studying their characteristics is your best plan for detecting altered surfaces.

“Dipping” a coin means to treat the coin in some sort of acid solution, with the intent of removing substances on the surface of the coin. While a nearly imperceptible amount of metal is removed, the flowlines on the surface of the coin are similarly miniscule. Dipping a coin improperly, or multiple times, will continue to affect these microscopic flow lines, leading to muted or dull luster. An “improperly” dipped coin will have traces of dip residue remaining on the coin. Circulated coins which are dipped will look ridiculous – the surfaces should have a patina and a layer of dirt.

Other, harsher forms of cleaning are not quite as benign. A common method is to use some sort of polishing paste and a rag to clean a coin, similar to polishing silverware. Below are pictures of a series of coins on which I took a paste of baking soda and water, and aggressively polished each coin for approximately a minute, using either a Q-tip or a paper towel. The baking soda makes a fine gritty paste, which would be perfect for polishing coins. As you can see, the characteristic of cleaning with this method is a bright, shiny surface.


(Original Lincoln cent on left, polished Lincoln cent on right)


(Original Roosevelt dime on left, polished Roosevelt dime on right)

The next method I want to discuss is most evident on proof coins. The ambitious cleaner will take a jewelers rag and wipe the surfaces of a coin. Proof surfaces, with their delicate mirrors, will show myriad fine hairlines. These hairlines are not usually considered severe enough to result in a details grade, but hairlines will definitely detract from the grade.

To see just what effect a jewelers rag would have on a coin, I took the Sacagawea proof shown below and subjected it to a quick wipe. I only wiped the field twice, but the hairlines quickly and unmistakably appeared. As expected, they only showed up under strong lights, and then only at certain angles. Look at the third photograph – the hairlines are present on the coin, but are completely undetectable in this picture.


(Reverse field of a Sacagawea proof, before any polishing)


(Reverse field of Sacagawea proof, after being polished. The hairlines are impossible to detect under these lighting conditions)


(Reverse field of Sacagawea proof, showing hairlines)

The final type of cleaning which we will discuss in this article is polishing with a wire brush. The surfaces of these coins will look exactly like you think – numerous fine hairlines cover the surface of the coin. These coins will have an appalling sheen when angled to the light, but only at the angle of the brushing. At any other angle, the coin will appear dull and lifeless.


(Heavily polished coin)


(Same coin, at an angle such that the polishing is nearly undetectable)

WHIZZED COINS
One of the most severe forms of cleaning, and deserving its own discussion due to its pernicious nature, is Whizzing. Some entrepreneurial coin doctors have taken rotating wire brushes or dremel tools to coins, in order to simulate the lustrous surfaces of original, high grade coins.

The coin shown below is by far the most expertly, and extensively, whizzed coin that I have ever seen. Notice in the full coin pictures how the coin appears lustrous and well detailed, but something just doesn’t seem right about it. There is a glow about the coin that can really only be described as unnatural. Now, look at the close-ups of the coin – magnification reveals that some sort of tool was used over the entire surface of the coin to produce artificial luster.

Whizzing often produces a telltale pattern from the back and forth action of the dremel tool. In the magnified close-ups, notice how there is a distinct pattern to the damage. Flowlines tend to emanate out from the center of the coin, so an expertly whizzed coin will simulate this pattern. This pattern, moreso than any other diagnostic, is indicative of whizzing.

Another characteristic of cleaned coins that is exhibited to great effect on this coin is the area around protected devices. The very small angles and tight spaces immediately around devices tend to be protected from the damaging effects of coin doctors. These areas will stand out from the surrounding fields, and tend to give the coin an even more unnatural look.







(Numerous shots of a heavily whizzed coin)

THOUGHTS ON SURFACES

The Third Party Graders are very good at detecting surfaces which are not original. If the problems are too severe, they will either bodybag a coin, or will put it in a holder with a details grade. PCGS labels a coin as genuine and gives a code for the specific problem, while NGC is much more descriptive. They will label the slab with a description of the problem, using a large number of descriptive terms such as corroded, environmental damage, stained, polished, whizzed, wiped, etc. When grading a coin yourself, it is always good to impart some information about the quality of the surfaces of a coin, if necessary. To say a coin grades EF is one thing, to say it has EF details with wiped surfaces is completely different.

Many numismatic materials are highly reactive with their surrounding environments. The delicate surfaces will develop problems, often with disastrous consequences. Coins which were buried in the ground can often corrode to the point that they are unrecognizable. Coins can also become porous, such as the 2 cent coin shown below. When grading a coin of this sort, the surface problems must be taken into account. Other naturally occurring surface problems can include the “shipwreck effect,” found on coins which have been recovered from seawater.


(Porous copper coin)

I hope this helps stimulate a discussion about altered surfaces!

 

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Another informative write up, great information which should be required reading for all new collectors. Good work!

 

Very nice write-up, Jason. A little scary how 'well' that Roosevelt dime polished up, though!

 

Great write up!

 

Learned a lot from your last two posts, thanks for doing this.

 

Jason, did you really mean this:

The baking soda makes a fine gritty paste, which would be perfect for polishing coins

I thought using baking soda on coins left hairlines.

 

Nope. I wrote exactly what I meant. Baking soda does not leave hairlines- it leaves a strangely smooth and unnaturally reflective surface. The coin is polished. You can clearly see the results in the picture of the Roosevelt above - with no hairlines.

 

wow...this is really helpful. Thanks
Do you have any example of cleaned nickels (eg: buffalos) ?
In any case, great writeup

 

Thanks!

I don't personally have any pictures of cleaned buffs, but someone else here might.

 

thanks, I suspect I do as I've purchased some as well as mercs without the proper background. Will take a look at your book