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!