Featured How to Detect Cleaned Coins

Discussion in 'US Coins Forum' started by TypeCoin971793, Nov 24, 2018.

  1. TypeCoin971793

    TypeCoin971793 Just a random nobody...

    This is an article which I started a while ago, but did not get around to finishing it. Recent discussions have inspired me to finish it.

    To begin, let’s define what a “cleaned” coin is. A coin is “cleaned” when any material is removed from the coin. This includes everything from using canned air to blow off dust to using iron wool to scrub a coin clean. There are two levels of cleaning: “proper” cleaning and “improper” cleaning. If an experienced collector/dealer/grader cannot tell that a coin has been cleaned, then it has been properly cleaned. If they can tell, then it is improperly cleaned and should be considered damage. From here on out, I will used the word “cleaned” to refer to “improperly cleaned.”

    When I look at a coin, I use a three-step process each time to determine if the coin is cleaned. The three steps are as follows:

    1. Grade the Coin

    2. Look at the Color

    3. Observe the Surface Quality

    Here is a breakdown of each step:

    Step 1: Grade the Coin:

    Half of the battle is determining the coin’s grade. When you look at a lot of coins, you will get a feel for what a coin should look like for a given grade. This is instrumental in detecting cleaned coins because an improper cleaning will permanently alter the coin’s appearance. Here is a brief grading lesson:

    MS: No wear whatsoever. Luster should be complete in the fields and the high points.


    AU: Some little to moderate wear on the high points. There should still be luster in the fields or on the devices. The breakdown I use is 58: 90+% of luster present; 55: 70-90% of luster present; 53: 40-70% of luster present; 50: 10-40% of luster present. These numbers are approximate and will vary from person to person. The upper coin is graded AU-58 and the lower one is graded AU-50


    EF: and EF-45 should still have some luster hugging the devices, and usually less than 10% of luster is present. EF-40 usually no luster, though some issues might still display luster even down to the VF level (Capped bust halves come to mind). As with everything, there are always exceptions. This is where you need to learn strike and wear patterns to determine an accurate circulated grade. The coin pictured below is graded XF-45. Note how there is weak luster immediately around the peripheral devices.


    VF and lower: There should be no luster, but some series have luster down to the VF level (notably capped bust halves). You will need to learn the wear characteristics of the coin series to narrow it down further. Generally at this level copper and silver coins obtain a medium-to-dark patina, though some coins that circulated to 1964 and later will not have the darker toning.


    You may notice that I may do most of my grading using the presence of luster, which is the first thing that the Third Party graders look for when grading a coin. So what is it? Luster is basically microscopic metal flow lines that are etched into the die. When a die is brand new, it is polished and completely smooth. This smoothness will transfer a mirror-like finish to the coin, creating proof and proof-like coins. When a coin is struck, metal flows into the incuse areas of the dies (devices) and towards the rims. This flow of metal will etch radial lines into the die. As more coins are struck by these dies (usually after 2000-4000), the proof-like surface qualities disappear, and the surface of the struck coin will display the etched flow lines of the die. Modern Canadian bullion rounds have small radial lines on the obverse and reverse, and it is an excellent representation of what luster looks like on a macroscopic scale. It will cartwheel just like a BU Morgan Dollar.


    These microscopic ridges will scatter any incident light, so the coin will often look matte or “frosted.” Incident light will hit the top edge of some of these lines, and this will create the “cartwheel luster” effect. The luster will always have a cartwheel, even if it is worn away to the point that it is just hugging the devices. For detecting luster on circulated coins, look for a bright-colored halo around the devices. If what you are seeing is actually luster, it will “pop” out of the surrounding surface. If not, then it is probably not luster.


    Another tip for grading coins is to know the strike characteristics of a certain date, type, or variety. What can look like wear may actually be a weak strike. For example, take a gander at this bust half:


    There is very little detail immediately visible, making it look like a low grade. However, if you look closely, you can see that there are some characteristics that are not consistent with lower grades. There is luster hugging the stars and letters, and the stars and right wing (Eagle’s left) feathers are very detailed. As such, it must be graded around EF-45, which is what PCGS graded this coin.


    This is where experience comes in, and specialists will have the best feel for grading the coins in their area.

    I will post each of the three steps separately due to the number of pictures. Stay tuned!
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  3. TypeCoin971793

    TypeCoin971793 Just a random nobody...

    Step 2: Look at the Color:

    This step is the one I use the most when I try to determine if a coin is cleaned. The trick here is to know what a coin is supposed to look like in a specific grade. Any deviation from that expectation should be looked upon with scrutiny.

    Important Notes on color for Original Coins:

    • Silver tones naturally, and the presence or absence of luster determines color
    • Lustrous coins usually have rainbow toning when they are toned.
    • Circulated coins have dull medium to dark gray toning, with exception of many post-1916 coins because any accumulated patina was continuously rubbed off in circulation. Pre-1878 coins were subjected to highly-sulfurous air from the industrial revolution which caused accelerated toning when they were pulled out of circulation. The air quality was much better after 1964 when the “junk” silver was pulled out of circulation, so they didn’t tone as quickly, which is why the coins in “junk” silver bins are not darkly toned.
    • Copper naturally tones from red to brown, despite the presence of luster. Lustrous “brown” cents can have rainbow toning.
    • Some copper coins have a “wood-grain” texture from alloy-mixing issues.
    • Gold normally does not tone (though there are exceptions because of alloy mixes), so this section can be ignored with respect to gold coins.
    Again, I use that “luster” word again. Why is it important here? The answer is that coin luster has a reflectivity that circulated coins do not have. When light waves hit a lustrous part of the coin, the light is reflected off of the coin instead of being absorbed by the metal. When this happens through a patina (or “toning”), a phenomenon called thin film interference occurs, resulting in a rainbow of colors on a coin’s surface. When the light is absorbed by the metal, you don’t get thin film interference and you get a dull grey or brown color, depending on the metal.

    An original lustrous UNC coin:


    An original EF coin:


    Older coins toned because they were pulled out of circulation and set aside during a time of lots of dirty industry, so there was lots of sulfur in the air. Every time a coin sat somewhere for an extended period of time, it would quickly try to patinate until it would be wiped off when the coin was spent. Larger coins were often hoarded and not spent because of their large buying power, so repatination was easy. This was less common with smaller denominations minted after the Civil War. When a coin was spent, there was a little rubbing on the high points that wiped the patina off these areas, making the patina on the high points thinner and thus a lighter grey because it absorbed less light. This is called a “circulation cameo”, and it is often a good sign of originality.

    Color on circulated coins is not always a bad thing. As stated earlier, luster is present on the upper circulated grades. This luster is key for rainbow toning to form, so where there is luster on a circulated coin, there can be rainbow toning. Notice how on the below examples that where the luster ends, the rainbow toning also abruptly ends.



    Here is an original copper coin with a nice brown color.


    And here is an example of a copper coin with a woodgrain coloring

  4. TypeCoin971793

    TypeCoin971793 Just a random nobody...

    Important notes on color for cleaned coins:

    • Shiny and glossy surfaces are bad (NOT to be confused with Lustrous or Prooflike). Naturally-toned circulated coins will have dull surfaces.
    • Rainbow toning on circulated coins in areas without luster is bad because that means that the surface was messed with to make it more reflective to induce thin film interference.
    • White or pale grey on pre-1878 silver coins is usually bad because the environmental conditions of the time strongly induced toning.
    • Darker toning (NOT DIRT) around the devices is usually bad. This is the result of a previous patina being removed, and the cleaning device not being able to reach the area immediately around the devices. The change must be sudden and drastic. Circulation can mimic this effect, but the change would be gradual.
    • Orange and Pink on copper coins is BAD. Copper just does not tone these colors.
    • Black on coppers is BAD. This is the terminal state of a copper coin with cleaned surfaces.
    Here is an example of a silver coin with pale, glossy surfaces from a cleaning:


    Here is an example of a silver coin without luster having rainbow toning. This coin has been cleaned or dipped.


    The blast-white appearance of this seated half without luster is indicative of it being cleaned. The dealer I was considering buying this from said he dipped it himself and it has no luster.


    Here is an example that has a dark halo around the devices from a cleaning which did not successfully remove all of the patina around the devices.


    This cleaned copper coin has a glossy orange color


    The glossy black surfaces on this copper coin indicate an old cleaning.

    Last edited: Nov 24, 2018
  5. TypeCoin971793

    TypeCoin971793 Just a random nobody...

    Step 3: Observe the Surface Quality

    The final step is to take a closer look at the coin to observe the surface quality in terms of hairlines and the like. There are some important steps to take in this step:

    • Lighting from a 60W - 100W incandescent bulb works best. This will reveal most of the problems present.
    • Rotate the coin under a light. This will change how the light shines on the coin, which will cause problems to jump out as the light catches them.
    • Use magnification if needed to get a better look at anything that jumps out in the first two points.

    What are you looking for by doing this? Well, three things:

    • Presence/absence of cartwheel luster
    • Unnatural “luster” (whizzed coins)
    • Hairlines
    When considering hairlines, there are two types of hairlines: circulation hairlines and cleaning hairlines. Fingers are abrasives which can cause hairlines on coins, so it is important to be able to tell the difference. Hairlines from circulation are small and scattered with no purpose. They often appear on the high points and in the middle of the fields. The AU-58 Morgan posted near the top shows this. Cleaning hairlines are long, parallel, and have purpose. The distinction is most easily seen on circulated gold coins because they don’t tone over the circulation hairlines.

    Here is an example of why rotating the coin under a light. This is the same coin under two different lighting conditions. The hairlines were not readily visible at first, but changing the light angle made them quite apparent. Also note how they are long and parallel. This is the classic sign of an abrasively-cleaned coin.


    Here is another example taken from multiple lighting conditions. The untoned surfaces are a glossy gray, there is color despite the lack of luster, and there are long hairlines that appear to move around in the right obverse field (among other places). All three aspects lead to the conclusion that this coin has been cleaned.


    “Whizzing” is a whole different animal. This is when a brush on a high-RPM tool is used on a coin to artificially simulate luster. Most call it tooling, but since someone could inadvertently use this method as a genuine attempt to “clean” a coin, I will include it in this discussion. A whizzed coin is best spotted through the unnatural appearance of luster and built-up metal around the devices from when the coin’s surface literally melts from the high friction. By “unnatural” I mean spread-out and liquid-like, which also spreads to the devices. It is an acquired eye, but it really jumps out when you see it if you know what natural luster is supposed to look like.

    Here is an example of a whizzed shield nickel. Note the wide spread of the luster and the unnatural patterns in the field.


    Lastly, some remarks about dipping:

    • Dipping a coin is not necessarily bad when done to an AU-55 or above coin. There is still plenty of luster at this level to make it not look completely unnatural.
    • Dipping can bring out luster and eye appeal if done correctly and on a coin that could be improved. It only “Resets” the surface of the coin if done right.
    • Dipping is not considered damaging (if done right), but should NOT be considered original
    • Dipped coins are often called problem-free if the luster is not impaired.
    • Dipping coins which grade below AU-55 will make coins look unnatural and will bring out circulation hairlines that were originally covered by a layer of toning.
    I hope this guide has been helpful and will be useful. These are the standards I use when calling a coin cleaned as they make logical sense to me. Use them if you wish, or make your own standards. Please feel free to add on anything I missed.
    Sardar, Tlberg, Mernskeeter and 17 others like this.
  6. 1916D10C

    1916D10C Key Date Mercs are Life! 1916-D/1921-D/1921

    Overall a very decent write up. A few questions:

    Have you read "The Art And Science Of Grading Coins" by Jason Poe?

    And also you mention magnification yet not what power- what kind does one use? 5x? 10x?

    Can you elaborate on this statement:

    TypeCoin971793 likes this.
  7. TypeCoin971793

    TypeCoin971793 Just a random nobody...

    No, but I want to when I get the time.

    I use a 10x

    What are you confused about? Which part would you like me to elaborate?

    Well, for one “black” should be “darker”. When a toned circulated coin is carelessly cleaned, it will strip off the layer of patina. However, the cleaning tool might not reach the small spaces around the devices, which will leave the original surfaces. When the coin retones, these areas will always be darker than the surrounding areas.
    Pickin and Grinin and 1916D10C like this.
  8. 1916D10C

    1916D10C Key Date Mercs are Life! 1916-D/1921-D/1921

    Good deal.
    Rheingold and TypeCoin971793 like this.
  9. SilverDollar2017

    SilverDollar2017 Morgan dollars

    Hoky77, TypeCoin971793 and 1916D10C like this.
  10. ldhair

    ldhair Clean Supporter

    Last edited: Nov 25, 2018
    Kentucky, CoinCorgi and baseball21 like this.
  11. 1916D10C

    1916D10C Key Date Mercs are Life! 1916-D/1921-D/1921

    Everybody knows Typecoin needs to take a chill pill. But that doesn't mean you should bash him or disregard his knowledge based on your disagreements with him around the board. I have bickered with you and LeHigh more times than I can count here and on other boards in the past 8 years, but that doesn't mean I don't respect you both in your expertise. And didn't you just get done telling me that picking fights is stupid? Come on Idhair, let it go and let's all try to get along.

    "I have never met a man so ignorant that I could not learn from him." - Galileo
    Last edited: Nov 25, 2018
  12. Seattlite86

    Seattlite86 Outspoken Member

    Thanks for the write up. Lots of good information here.
    TypeCoin971793, dwhiz and 1916D10C like this.
  13. TypeCoin971793

    TypeCoin971793 Just a random nobody...

    Before disregarding the information based on who posted it, try reading it.
  14. ldhair

    ldhair Clean Supporter

    I edited my post. I'm sorry. I was rude.
  15. Seattlite86

    Seattlite86 Outspoken Member

    I just wanted to tip my hat to you and say that I think you made a great move. Very gentlemanly of you.
  16. Dynoking

    Dynoking Active Member

    Thank you for taking the time to put this very informative thread. The pictures and your writing are clear and concise.
    TypeCoin971793 likes this.
  17. Thank you, very good info.
    TypeCoin971793 likes this.
  18. CasualAg$

    CasualAg$ Corvid Minions Collecting

    Very good and necessary information, especially for new mismatists.

    Thank you for taking the time to do this. I’m sure I’ll be re-reading this many times.
    TypeCoin971793 likes this.
  19. gbandy

    gbandy Junior Member

    Really appreciate the write up here. I did not realize how complicated this subject is.
    TypeCoin971793 likes this.
  20. Mountain Man

    Mountain Man Well-Known Member

    This sure beats what the one and only coin dealer in my area told me when I asked him how he could tell my Morgan had been cleaned. Instead of explaining it to me, he simply stated, "40 years of experience is how I know."
    Thank you for the information and photos.
  21. TypeCoin971793

    TypeCoin971793 Just a random nobody...

    I’ll add this to this thread as it is relevant:

    While we're on the subject of hairlines, here is a a quick little diagram that I just made. The top left is the hairlines one would expect on a problem-free AU coin, while the top right is the hairlines one would expect on a problem-free heavily-circulated coin. The key here is that the hairlines are purely random and, for the most part, short.

    The middle left example has a patch of hairlines where a small portion was cleaned, like with a cloth or a Q-Tip. Note how the hairlines are long and have a deliberate pattern to them. Also note how the hairlines spread onto the devices (die polish lines do not do that). The middle right example has a larger patch.

    The bottom left example has had the entire surface cleaned. For this example, a cloth/brush/etc was used in a circular motion over the entire surface. Again, notice the length and deliberate pattern. The right bottom example has had a lateral wiping/brushing, so the hairlines cover the coin in only one direction.

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