Coin cleaning. An acceptable way?

Hello all,

I have a question. I understand that cleaning coins can devalue them. I've read this in numerous books and online. What I'm not sure of is whether this policy is strictly referring to aggressive cleaning methods (electrolysis, scrubbing), or any and all cleaning methods.

Can you tell me, please, are there any acceptable cleaning methods, numismatically speaking?

 

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Yes, there are "acceptable" cleaning methods. More importantly, there are acceptable reasons for cleaning a coin. None of those reasons involve the owner's enjoyment - or lack thereof - of the coin's appearance, and that's where collectors go wrong.

There are chemical process which, left unarrested, will damage the surface of a coin permanently. These must be dealt with, and the appropriate methods can be described as "cleaning" even though the appropriate term when you're doing it for the right reason is "conservation."

There are coins (dug, ancients) so encrusted/corroded that intrusive methods ought to be used to make the coin more visible and identifiable.

That's it. The only reasons to clean a coin. There are fairly non-intrusive methods and chemicals (acetone for instance) which can be employed without themselves damaging the coin.

 

I wouldn't recommend cleaning coins Because it can ruin them and take the value out of it. However there is some ways that MIGHT ruin your coin.
Here is where I got some info... https://coins.thefuntimesguide.com/2008/01/how_to_clean_coins.php
the pencil eraser works, the baking soda works for quarters, nickels, dimes, & halves.......

 

Andy, you should never use a pencil eraser. This is something that many of us did as kids before we knew better. Please use Daves post above as a starting point and learn more about it through the various posts here. I'm sure someone here can refer you to past posts that are both correct and a must know before anyone attempts any kind of cleaning.

 

Thanks to everyone for the information thus far. I'll be sure to read the guide provide.

 

Depends how it's done and to which coins they are done. You definitely would not want to clean a modern US coin. If it has patina or toning, people like a good bit of color on their old coins, so I'd leave it as is. Besides, modern coins have fragile surfaces, so cleaning can damage them.

Now, if you are talking about ancients, yeah, cleaning often helps when coming fresh from the ground.

 

Eric, just type in coin cleaning into the search box at the top right and see what happens. Should lead you to past posts. Of course you will need to sort out the chaff as the old farmers say and take the best posts. There's a lot of good info here.

 

And (sometimes) necessary if metal detecting and old copper finds.

 

I second the acetone suggestion that @SuperDave made. Acetone is very good at removing organic compounds (like PVC) but doesn't react with silver or silver sulfide. Be careful using it with copper, though, because it supposedly does something really weird and discolors copper coins if you're unlucky.

 

For crying out loud, what a terrible thing to post as "reputable." It's a laundry list of the things which damage coins the worst.

 

No kidding, why not just throw gasoline on the coin and light a match? That'll clean it too....

 

The best thing for us average collectors to do is NOT to clean coins. The risks, in my view, far outweigh any positives.

 

Brillo pads work good as does steel wool. Sandpaper for tougher cases. And when you really wanna clean it either a polishing wheel or a belt sander. Aqua regia works really well on gold coins too

 

High percentage alcohol sometimes helps cleaning gold coins and is harmless.

 

What about using a professional coin cleaning service? Still a no go?

 

I think a better approach here is to think about what you mean by cleaning a coin. Are you trying to remove foreign material from the coin's surface, like dirt, dust, grime, etc. Or are you trying to alter the surface of the coin, i.e remove oxidation or otherwise change the surface material of the coin.

In my view, the first is almost always acceptable and I would go so far as to say prudent in the case of copper coins. Dirt, oil, and other grime left on a copper coin will over time cause corrosion, so removal is an appropriate part of conservation.

On the other hand, altering the surface of a coin is almost never a good idea in my opinion. Toning, regardless of how ugly it looks, should be left as is. Details should never be strengthened, corrosion should never be smoothed. Anything that alters the metal should be avoided.

The trick is knowing the techniques that will safely remove foreign material while not reacting with the underlying metal. This process will be different depending on the metal used in the coin. If you are going down this road, do your research and test on coins with no numismatic value first.

 

Does the alcohol go ONTO the coin or INTO the owner?

Just sayin'... ;-)

 

Thank you. And to clarify, my original post was in reference to the removal of dirt and grime. I would never want to alter a coin's fundamental material or structure.

 

Perhaps a specific example will help guide the discussion. I have a beautiful 1924 Peace Dollar that very clearly has some dirt and grime. I would be fine leaving the coin as is, but would prefer to remove some of the dirt that has built up on it. If doing so would devalue the coin, I would leave it alone. If I can clean this coin without affecting its material and/or structure, and still have it be numismatically appealing, then I would want to do so.

 

I've used distilled water, acetone, xylene, and verdicare to conserve coins before TPG submission (depending on the coin). Just light soaks or rinses without anything touching the surfaces of the coins except the liquid and then I stand the coin up on edge to dry briefly. I've sent in over a hundred coins for grading and I've never had one designated as details due to any of the above conservation methods.