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 Replies: 38 / Views: 3,443 |
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Pillar of the Community
 United States
6449 Posts |
I got this silver Washington quarter today in an ebay shipment. The coin is circulated and has a hazy "patina". I gave it a soak in hot water, then a three hour soak in pure acetone. However, that did not remove the substance. It is faintly sticky to the touch. Dissatisfied, I rubbed with a toothpick on the right obverse. That visibly disturbed the substance, and dark material stained the toothpick tip. What is this crud? Is it conservation-permissible to rub the side of a toothpick all over this coin to remove the film? Is there another conservation method that I should try first?   |
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Bedrock of the Community
 United States
24878 Posts |
Try different solvents - xylene, isopropyl or ethyl alcohol, etc. Paint thinner if necessary (not recommended for collector coins).
Inordinately fascinated by bits of metal with strange markings and figures
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Pillar of the Community
 United States
6449 Posts |
Is alcohol going to dissolve anything that acetone wouldn't?
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Bedrock of the Community
United States
17884 Posts |
Another possibility is Methyl ethyl ketone (MEK)
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Bedrock of the Community
United States
24878 Posts |
Yes. For instance, sugar is not very soluble in acetone but is somewhat soluble is alcohols. Acetone is a good solvent but not a universal one. Something deposited the goo on your coin, and you have to approximate that solvent through experimentation.
Inordinately fascinated by bits of metal with strange markings and figures
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Pillar of the Community
United States
6449 Posts |
I am still new to cleaning and conserving coins. Mostly what I know is BadThad's polarity ladder of Distilled Water > Acetone > Xylene > Sodium Sesquicarbonate > Verdicare, as demonstrated by DOCC. But the only coin-safe solvents I currently own are water and acetone.
Is there a coin conservation site somewhere that discusses what solvents are effective against what deposits?
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Pillar of the Community
United States
3169 Posts |
There is always E-Z-Est Coin Cleaner, but
I have used the old tinfoil and salt trick, it works.
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Pillar of the Community
United States
3169 Posts |
I'm afraid this one may not come out looking
good without rubbing, no matter which method.
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Bedrock of the Community
United States
24878 Posts |
This looks like a bullion-grade coin (unless I'm missing something) so I would try things that are normally not recommended. Were it mine, I would first try rubbing alcohol and use my clean bare fingertips to gently rub it (with much alcohol) to see if the gunk is removed. If that doesn't have any effect, try warm water and hand soap or liquid dish detergent.
Inordinately fascinated by bits of metal with strange markings and figures
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Pillar of the Community
United States
6449 Posts |
Hondo, it's actually a DDR. The coin is circulated, though. To my thinking, I see it this way: the coin has some sort of obvious contaminant on its surface. Nobody is going to grade this coin, even though it is a variety. So I don't see difference between Details: Gunk and Details: Cleaned. So if I have to rub the entire coin with a toothpick until all the gunk is gone, I kinda see that as the price of admission. |
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Pillar of the Community
United States
819 Posts |
I would put it back in the acetone and leave it for a day or two.
Three hours may not have been long enough.
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Bedrock of the Community
United States
10472 Posts |
It's a circulated 41 quarter - mostly a melt coin. But if a sticky substance try rinsing it with this "Goo Gone" adhesive remover, then soak in acetone. And do it outside - "Goo Gone" stinks like lighter fluid.  |
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Bedrock of the Community
United States
24878 Posts |
WD-40 takes off all kinds of sticky gums too.
Inordinately fascinated by bits of metal with strange markings and figures
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Bedrock of the Community
United States
24878 Posts |
Hey Marve, have you ever tried Goo Gone on a slab? I sometimes get slabs that have had stickers on them and it's tough to get that goo off.
Inordinately fascinated by bits of metal with strange markings and figures
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Pillar of the Community
United States
2520 Posts |
I haven't used on slabs but have used on plastic with success, but then you have to wash with soap and water to get the Goo Gone...Gone. It does have a smell and kind of greasy. Does come off with soap and water.
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Pillar of the Community
United States
7933 Posts |
You haven't tried a nonpolar solvent yet: mineral spirits, paint thinner, or xylene
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Replies: 38 / Views: 3,443 |
Posted 08/21/2025 3:09 pm
