Cleaning coins with a sonic jewelry cleaner.

Is it safe to clean coins in a sonic cleaner? If so which type are safe to clean? If so does it even help?

 

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This topic has come up before and so believe the overall answer was no it should not be used to clean coins.

 

NEVER CLEAN COINS!!!!!!

 

I agree with the sentiment and appreciate the enthusiasm, but just to clarify dipping silver coins in acetone isn't considered cleaning, is it? That seems to be the consensus that I've heard here. Is there anything else collectors do to their coins to conserve them that doesn't count as cleaning?

 

Coins are cleaned successfully all the time. Whether and and how it should be done requires expertise. Every ancient coin has been cleaned at least once. Ultrasonic cleaners can be helpful in some circumstances, but they can ruin a coin in others. Some coins may have hidden cavities, and ultrasound waves may cause the fluid in the cavities to expand and fracture the coin. It takes knowledge and experience to clean coins regardless of the method. In the hands of inexperienced amateurs, it can be a disaster.

Cal

 

A couple of thoughts.

Regarding acetone, I often use it to stabilize a coin that may have been handled with oily fingers. High grade circulation finds. No rubbing...just dipping and drying. A soak will sometimes also loosen up some debris and carry it away. This could be advantageous or ruinous. Depends on what it looks like once the process is over. Generally, I wont soak an older coin for fear of altering appearance, especially on a more notable coin. I'll accept the general buildup that comes with the coin.

Regarding conservation, perhaps using an ultrasonic cleaner, there may be a practical and pragmatic use for it. I would visit the folks that deal with Ancient coin conservation for a better opinion. But for some coins, especially massed coins that have to be separated for one another, the ultrasonic bath might be what is needed. Conservation has to be done on a number of those really old coins, but also on some of the 'newer' coins. Things pulled from a wishing well perhaps. I recall a 1909 VDB I found couldn't be ID'ed as it was. I soaked in distilled water to no avail. Soaked it in acetone and that didn't work either. I finally soaked the coin in Verdicare and the soiling started to lift and separate. Unfortunately, it left an uneven appearance, but at least the date was readily identifiable at that point. Oddly enough, the reverse was fine...and VDB readily apparent. I almost made a colossal mistake by missing the initials. Had I noticed, I would have opted for a professional conservation. If there had been an S, I could have depreciated that coin significantly.

Conserve rather than clean. But many will argue, that conserving IS cleaning. So find where you sit on the issue before you do either.

 

Thank you for the wisdom - I think I sit in the camp that would just rather pay ICG an extra $5 to conserve my $10 economy submissions if I think it might be helpful and not worry about it myself.

 

...unless you know what you are doing

 

Many good thoughts to ponder. Thanks for all your inputs as always.

 

Imho... Dipping isn't considered cleaning

 

An ultrasonic cleaner would likely be useful for removing crusty dirt from crevices or protected areas. It would be of no use for things like ugly toning, where you might consider a dip, or waxy residues that acetone would be useful for.

 

Perhaps there exists a written thesis about "best practices" for conserving vernacular coins that are not to be submitted for grading. My collection of world coins consists of gently used coins, but often would look better without the grime and dirt. These are not rare nor highly valuable except as a reminder of travels and travails. Confession: I clean my coins such as those. Water, acetone, soap and even a gentle brushing. However I also have "collectable coins" which I would never clean myself, and would send to a conservator. I think a guide to such things would be very helpful.

 

Sonic cleaners will create rub on the surfaces of the coin. You would need to find a way to suspend the coin so it could not rub anything. Probably best to just not use one.

 

Perfect! That $10 economy submission has been making me think....

 

Would you recommend a cleaning on these coins?

 

Good choice.

 

Good humor!

 

Ancients yes, all others at your own risk! Personally, I do not. Just my opinion, good luck.

 

You are correct that if you allow the coin to sit on the surface of the Ultrasonic Tank it may result in friction on the Rim (that being the highest profile on a properly struck coin), and if not properly formed during the Upsetting Operation, on some of the highest Relief. Most Ultrasonic Cleaners will come with a Plastic Basket that is perforated to allow the Solution to penetrate and Cavitate around the coin while providing a softer surface than the coin metal so that friction does not occur. Now, putting more than one Coin into the Ultrasonic Cleaner (or its basket) at the same time may result in them moving into each other and even the lighter weight coin(s) moving on top of a heavier coin (as in some Ultrasonic Cleaners, depending upon the level of the liquid and the position of the Coin therein, there is significant movement and "jumping" do to the vibrations imparted by the Basket or Tank Surface and by the Cavitation Bubbles expanding). What I did initially to allow an even penetration of Solution along with maximum Cavitation is to take a woman's Nylon Stocking--cut along one seam and then opened flat--and make a "Holder" using a wire hanger that follows the interior contour of the ultrasonic Cleaner with 2 "Ears" that lay on top of the Ultrasonic Cleaner's Opening. The Stocking will stretch downward to allow the Coin to be held by the Edge so that it will not move, and when the cleaning is complete, the Holder is lifted up to remove the Coin. Later on, I purchased a Stainless Basket (from a Lapidary store) that already had a stainless steel mesh strainer attached, which I removed and replaced with the Nylon Stocking. There are commercial solutions from Jewelry and Lapidary stores that are available for general jewelry and gemstone cleaning, but some of these are ACIDIC in nature and I would strongly advise that you investigate the contents before purchasing. A good alternative is to use hot tap water with 1/4 teaspoon of Dawn Dishwashing Liquid, which containing both ionic and non-ionic surfactants, is effective for most organic and non-organic soils. If you have something like tar in crevices of the coin and you wish to effectively loosen--and possibly remove it completely--you can use a solvent such as Acetone or Trichloroethane in a tall glass jar with the Coin resting on the bottom of the Jar, and the Jar resting on the Tank Bottom (Yes, it does work).