DirtDodger
Jr. Member
Erik's question on cleaning & some info
"Does lightly rubbing a baking soda and water slurry on a silver coin constitute cleaning and thus devalue it to melt value? How about wetting it and wrapping it in aluminum foil then rinsing it in soap and water? Does soap and water cause it to be devalued? I'd like to know where the "numismatic" line is.
Some old & Spanish silver comes out of the ground almost black and I find it hard to believe that leaving it in that state would be the best approach. Any insights here?
I never got an answer to my prior post BTW from DirtDoger--my questions were sincere."
There are two types of cleaning for coins, often confused with each other.
Destructive cleaning uses abrasives or acids to clean (and alter) the coin surfaces. Non-destructive cleaning uses solvents that are harmless to the coin's metal, whether that coin be silver, gold, or modern clad composition. Baking soda is an abrasive. Not a wise choice if one is trying to preserve a coin or its numismatic value.
The metal cleaners you see offered for sale on TV and elsewhere all are acid-based cleaners. They remove some of the surface metal in the process of cleaning a coin. Avoid such coin cleaning products at all costs. Ancient coins or gold and silver coins will lose collector's value, and precious metal content through use of such cleaners.
Non-destructive cleaning: rinsing of soil and/or debris off. Logic dictates that you need to be able to see all the surfaces to evaluate the item. Even the American Numismatic Assoc. (ANA) says "you may try a solution of mild dish soap and distilled water. Rinse the coin thoroughly with distilled water and allow the coin to air dry". Numismatic Guaranty Corporation (NGC) advises "A weak soap (not detergent) solution in distilled water will remove dirt and grease from an encrusted coin without damaging it, even if the coin is one of those grimy specimens found at the beach. City tap water has chlorine in it, which will discolor the coin. Use distilled water, and rinse with distilled water."
With that said, not all coins are treated equal nor is there one simple answer. This is way I and many others advise it is almost always better not to clean coins other than to remove the soil. You can never unclean them, but you can clean them at any time needed in the future. It is like trying to un-ring the bell, once it's rung...
A few simple rules:
For all US minted coins, altering the surface almost always surface devalues a coin. Not always to billion value, it depends on the rarity and how and what destructive cleaning was done. Polishing is generally beyond even destructive cleaning. For a coin such as a 1943 half, not a valuable coin, even in an untouched state would not command much more than melt anyway. Thus as far as collectors go it would be melt value as others have stated. Now if it was say a coin worth hundreds or thousands it would not be reduce to melt value. Its value would likely drop substantially depending what was done to the surface. The reason for this is when a business strike is made; metal tends to flow in microscopic lines that often form radial patterns, which sometimes are reminiscent of the spokes on a wheel. The Mint luster this creates is a function of how metal flow lines on a coin reflect light. Such lines are usually pronounced on business strikes. Cleaning and handling wear down, damage or remove these lines which can be seen under 10x and 30x magnification. If you ever went to a coin show you will see many dealers using loops to view coins. This is one of the main things they are looking at.
Coins such as Colonial, Spanish silver and medieval hammered and ancient coins are in a totally different category. This is partly due to how they were made and the fact almost all of them were buried or lost at sea and over the centuries have been cleaned. It does not affect the value as much or at all. With coins made by hand, the surface is generally unlike one created with machinery. When machinery is used a higher stamp pressure is applied creating microscopic metal flow. Not having that kind of surface, non-harsh cleaning generally doesn't always harm or destroy the numismatic value. Rule of thumb here is using the lease abrasive method possible. Many of these coins retrieved from the ocean are cleaned through electrolysis a non-abrasive method. As for ancient coins many times the absence of patina is usually a warning to a collector.
Additionally, there are some DUG coins that you really can't devalue any farther by cleaning no matter how harsh including wire brushing and steel wool. Nickels and most copper coins. Their value to collectors is generally going to be at the very low end anyhow. The surface is generally been ruined to the point it can't go farther down unless you remove the date. Examples of this are liberty and buffalo nickels. No matter what method used to clean or polish them the value is not like to change much. The surface can never be restored. It's like trying to un-ring the bell.
Generally speaking though, trying to restore badly corroded coins is a waste of time. Even if you successfully remove the corrosion, there is usually permanent damage underneath, leaving you with a near worthless coin to numismatic collectors.
Speaking for myself, I would sooner have the coin as it was dug than having the surface destructively cleaned.
Some folks insist on cleaning their coins. The typical response from people who don't take advice kindly is "I'll do as I please with my coins".
I say onto you... no one is stopping you... but "Sometimes it hurts so badly I must cry out loud" (CSN) when it's done...
With that all said there is always exceptions to the rules as some here have clean coins and claim they gotten more money from them on places like Ebay etc.... This is generally not the rule and I suspect most of those buyers don't truly understand numismatics.
As always don't listen to just me or anyone on a forum educate yourself, here are a few places to start...
Money.org · Money Org
PCGS The Standard for the Rare Coin Industry
Professional Numismatists Guild , PNG Dealers, Rare Coin Dealers, Paper Money Dealers, Precious Metals Dealers
Third-Party Coin Grading | Numismatic Guaranty Corporation (NGC)
eacs.org
"Does lightly rubbing a baking soda and water slurry on a silver coin constitute cleaning and thus devalue it to melt value? How about wetting it and wrapping it in aluminum foil then rinsing it in soap and water? Does soap and water cause it to be devalued? I'd like to know where the "numismatic" line is.
Some old & Spanish silver comes out of the ground almost black and I find it hard to believe that leaving it in that state would be the best approach. Any insights here?
I never got an answer to my prior post BTW from DirtDoger--my questions were sincere."
There are two types of cleaning for coins, often confused with each other.
Destructive cleaning uses abrasives or acids to clean (and alter) the coin surfaces. Non-destructive cleaning uses solvents that are harmless to the coin's metal, whether that coin be silver, gold, or modern clad composition. Baking soda is an abrasive. Not a wise choice if one is trying to preserve a coin or its numismatic value.
The metal cleaners you see offered for sale on TV and elsewhere all are acid-based cleaners. They remove some of the surface metal in the process of cleaning a coin. Avoid such coin cleaning products at all costs. Ancient coins or gold and silver coins will lose collector's value, and precious metal content through use of such cleaners.
Non-destructive cleaning: rinsing of soil and/or debris off. Logic dictates that you need to be able to see all the surfaces to evaluate the item. Even the American Numismatic Assoc. (ANA) says "you may try a solution of mild dish soap and distilled water. Rinse the coin thoroughly with distilled water and allow the coin to air dry". Numismatic Guaranty Corporation (NGC) advises "A weak soap (not detergent) solution in distilled water will remove dirt and grease from an encrusted coin without damaging it, even if the coin is one of those grimy specimens found at the beach. City tap water has chlorine in it, which will discolor the coin. Use distilled water, and rinse with distilled water."
With that said, not all coins are treated equal nor is there one simple answer. This is way I and many others advise it is almost always better not to clean coins other than to remove the soil. You can never unclean them, but you can clean them at any time needed in the future. It is like trying to un-ring the bell, once it's rung...
A few simple rules:
For all US minted coins, altering the surface almost always surface devalues a coin. Not always to billion value, it depends on the rarity and how and what destructive cleaning was done. Polishing is generally beyond even destructive cleaning. For a coin such as a 1943 half, not a valuable coin, even in an untouched state would not command much more than melt anyway. Thus as far as collectors go it would be melt value as others have stated. Now if it was say a coin worth hundreds or thousands it would not be reduce to melt value. Its value would likely drop substantially depending what was done to the surface. The reason for this is when a business strike is made; metal tends to flow in microscopic lines that often form radial patterns, which sometimes are reminiscent of the spokes on a wheel. The Mint luster this creates is a function of how metal flow lines on a coin reflect light. Such lines are usually pronounced on business strikes. Cleaning and handling wear down, damage or remove these lines which can be seen under 10x and 30x magnification. If you ever went to a coin show you will see many dealers using loops to view coins. This is one of the main things they are looking at.
Coins such as Colonial, Spanish silver and medieval hammered and ancient coins are in a totally different category. This is partly due to how they were made and the fact almost all of them were buried or lost at sea and over the centuries have been cleaned. It does not affect the value as much or at all. With coins made by hand, the surface is generally unlike one created with machinery. When machinery is used a higher stamp pressure is applied creating microscopic metal flow. Not having that kind of surface, non-harsh cleaning generally doesn't always harm or destroy the numismatic value. Rule of thumb here is using the lease abrasive method possible. Many of these coins retrieved from the ocean are cleaned through electrolysis a non-abrasive method. As for ancient coins many times the absence of patina is usually a warning to a collector.
Additionally, there are some DUG coins that you really can't devalue any farther by cleaning no matter how harsh including wire brushing and steel wool. Nickels and most copper coins. Their value to collectors is generally going to be at the very low end anyhow. The surface is generally been ruined to the point it can't go farther down unless you remove the date. Examples of this are liberty and buffalo nickels. No matter what method used to clean or polish them the value is not like to change much. The surface can never be restored. It's like trying to un-ring the bell.
Generally speaking though, trying to restore badly corroded coins is a waste of time. Even if you successfully remove the corrosion, there is usually permanent damage underneath, leaving you with a near worthless coin to numismatic collectors.
Speaking for myself, I would sooner have the coin as it was dug than having the surface destructively cleaned.
Some folks insist on cleaning their coins. The typical response from people who don't take advice kindly is "I'll do as I please with my coins".
I say onto you... no one is stopping you... but "Sometimes it hurts so badly I must cry out loud" (CSN) when it's done...
With that all said there is always exceptions to the rules as some here have clean coins and claim they gotten more money from them on places like Ebay etc.... This is generally not the rule and I suspect most of those buyers don't truly understand numismatics.
As always don't listen to just me or anyone on a forum educate yourself, here are a few places to start...
Money.org · Money Org
PCGS The Standard for the Rare Coin Industry
Professional Numismatists Guild , PNG Dealers, Rare Coin Dealers, Paper Money Dealers, Precious Metals Dealers
Third-Party Coin Grading | Numismatic Guaranty Corporation (NGC)
eacs.org
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