A question about removing some surface material from a coin

mercurydimeguy · September 7, 2005 2:40AM

OK...I'm stumped!

I would like to remove some green cruddy looking stuff from a coin -- as an experiment -- and I simply cannot without physically doing it. You might know what I'm referring to -- the stuff that sometimes builds up around lettering, devices, by the rim, etc. I suspect because it's a green paste-like substance that it's build up PVC, but do not know for sure. However, I have seen it on many coins before. Dip just removes(ed) the toning -- ok. Acetone (soaked for 1 day) did nothing...Neither did Blue Ribbon.

I put the coin under my microscope to test one tiny area...ever so gently with a toothpick I went over the surface of the green cruddy stuff that appears to be almost a paste-like substance. I was able to move if off the surface and on to the toothpick, being careful not to damage the surface. It worked but only when the coin was wet. However, there are some areas where the green cruddy stuff resides that I simply do not have anything that small to get in to...and I really can't imagine manually doing it as it would take me 4 hours if I was to be very careful...and I probably wouldn't be able to get it all off.

Isn't there a chemical that can remove it from the coin...if anyone has any experience and knows the kind of green cruddy substance I'm referring to please chime in.

Thanks in advance.

Veep · September 7, 2005 3:08AM

I don't know about green cruddy stuff, but I went after some black, cruddy stuff on an environmentally damaged, About Good 1916-D dime. What chemicals would not remove, I picked at with a needle under 30x magnification. It made the needle look like a railroad spike. Everywhere I picked, tiny, surface scratches appeared. That was expected. I was pleased because the the black stuff flicked right off. Then, I carried it around in my pocket with some other silver for a week or so. That removed the light scrathes and gave it a more natural look.

Hey, its still obviously environmentally damaged but much more pleasing to look at.

PerryHall · September 7, 2005 3:08AM

Can you provide a pic? If it is corrosion, removing it will leave a pit in the coin's surface.

Russ · September 7, 2005 3:14AM

Sometimes a day in acetone isn't enough. Could take a week, two weeks or even longer. Ancients collectors have been known to soak coins in olive oil for months.

Russ, NCNE

mercurydimeguy · September 7, 2005 3:14AM

I will provide a picture tonight, but no it's not corrosion. When I removed the substance with a toothpick in one area it didn't flick off...it's really more lilke a pasty texture. Then rinsing the coin underneath some running/filtered tap water, and then a quick rinse in acetone, that area looked great.

It's a common MS 3CS coin...yes I know a slightly pricey experiment but I'm a gluton for punishment

mercurydimeguy · September 7, 2005 3:16AM

<< <i>Sometimes a day in acetone isn't enough. Could take a week, two weeks or even longer. >>

Maybe this is the ticket...perhaps I've gotten used to acetone taking the thin film PVC type stuff off of coins in a matter of minutes...and perhaps this is really built up PVC that will take acetone some time to dissolve.

Thanks....

BigD5 · September 7, 2005 3:17AM

"paste-like substance" hmmmmm. Try Goo Gone. It may not be pvc slime if acetone and/or dip didn't remove it.

Actually, let's start over. When you soaked the coin in the acetone, did you use a Q-tip to lightly aggravate the coins' surface while it was soaking?

If you didn't lightly go over the surfaces with a Q-tip while it was still wet/soaking, that may be what needs to be done.

Tough to tell for sure without seeing the coin and the gunk.

If it is indeed full blown corrosion, acetone, goo gone etc. isn't going to take care of the problem for you.

mercurydimeguy · September 7, 2005 3:25AM

If you didn't lightly go over the surfaces with a Q-tip while it was still wet/soaking, that may be what needs to be done.

Ah, yes, an excellent idea. It did seem to come off fairly easily while the coin was wet. Kind of difficult to do though because acetone evaporates so quickly.

Should I soak a Q-tip in acetone and try that? I don't see how I can do it while it is soaking in acetone...unless I pour the acetone in a flat dish, place the coin in the dish and while the coin is in the acetone gently try rolling over it with a Q-tip.

BTW -- how would I try Goo Gone...in a similar manner as acetone, meaning just soak?

longtimecollector · September 7, 2005 3:55AM

Obviously you're not working with anything extremely valuable as you're hacking at it with a toothpick.........

You might consider trying an "ultrasonic" cleaning machine..... The right cleaning fluid / ultrasonic combination can yield surprisingly nice results !!!

If you don't have one, ask your local dealer / jewelry store

mercurydimeguy · September 7, 2005 3:58AM

The right cleaning fluid

What might this be or what would be your knee-jerk recommendation in this instance

Conder101 · September 7, 2005 9:42AM

If it is a pasty substance it is probably just skin oils and dirt.

Just soaking in acetone may not do anything, some agitation is needed. Possibly just swishing the coin around in the acetone may be enough.

Another possibility is that the material is water soluble not organic solvent soluble. Try a little soap and water. Especially if you can use a ultrasonic cleaner. That will probably take it right out.

morgannut2 · September 7, 2005 9:52AM

Do what LONGTIMECOLLECTOR said to do---most jewelry stores can handle it easily. If that doesn't work, it really is a job for the chemistry boys at NCS. Silica gels chemically oxidizing with silver/copper present will produce green gummy compounds--for example, the silver Comstock Load was discovered when a wagon got stuck in green goo over silicate/silver volanic rocks.

MrSpud · September 7, 2005 9:55AM

You can also try EDTA. It is supposed to chelate and remove certain corrosion products but not affect sulfur toning or the base metal. Here is a link to an old thread with EDTA info Old EDTA Thread . And here is a link to an experiment I did a while back to remove gren stuff from an old copper coin EDTA Experiment . Some people liked the result while others didn't like the way the copper coin came out. Maybe it will work better if the coin isn't copper though.

coinbuf · September 7, 2005 10:07AM

Another good tool is a rose thorn, its not as prone to scratching the surface like a toothpick is.

Chris

morgannut2 · September 7, 2005 10:09AM

I've used EDTA for "copper spots" (copper cloride/copper silicate in the motto of a 1894 Silver dollar)-- and it worked great, together with ultrasound. The problem is you need a chemistry degree (actually a spare chemist) to get the Ph balance right (neutral) as well as an ultra-sound machine. It's just cheaper to let NGC/NCS fool with it. But if you feel like trying it, please keep photo's. Good luck!

nankraut · September 7, 2005 10:12AM

Baking soda!

BigD5 · September 7, 2005 10:53AM

Keep the coin in a dish with acetone in it. While the coin is in the acetone, LIGHTLY agitate the coins' surface with the Q-tip. Be patient, and keep changing the Q-tip as it gets gunked up. Do not apply even moderate pressure. Keep it light.

I only suggested Goo Gone if it wasn't pvc, and was some sort of "gunk" possibly left over from adhesive, or tape, or something similar.

sumnom · September 7, 2005 12:38PM

Acetone works very nicely in getting rid of old adhesive as well.

sellsatan · September 7, 2005 4:35PM

I tried the olive oil trick Russ mentioned on a few coins as an experiment. It was not successful even after two months.

mercurydimeguy · September 7, 2005 10:19PM

I've done acetone and 95% of the stuff came off. In fact even using a 10X it just looks like ? "toning" ? Only when I throw under my scope do I really see it. I just have a feeling if I don't remove it ALL, it will grow back and then some.

Thanks for all the input thus far -- I'm going to order and ultrasonic and play around with that for a while

mercurydimeguy · September 29, 2005 11:56PM

Sorry I had forgotten about this thread...anyway, here is what the before picture looks like:

Bought it off of Telertrade in an Anacs 62 holder, paying $160 for it (that included the 10% juice and shipping). The coin looked much worst in hand -- not atypical. You can see the green paste kind of stuff on the coin.

....well, with the help of my microscope, some handy tools and recommendations from folks on this forum (thanks!), most of the stuff came off and the coin looked wonderful. I need the coin for my Type Set Registry Set. I sent it in using the free CC quarterly special. Grade just posted last night:

1 22081955 1853 3CS USA MS64

I'm very happy because now the coin looks wonderful, and it was saved from certain doom because the junk that was on it was only going to get worst and ruin the coin.

I'll post the "after" pics once the coin comes back from PCGS.

PerryHall · September 30, 2005 12:04AM

What kind of "handy tools" did you use?

LeeG · September 30, 2005 1:59AM

Very nice job. Congrat's!

majorbigtime · October 1, 2005 1:00AM

Try a Q-Tip

mercurydimeguy · October 1, 2005 7:19AM

I used Blue Rribbon soaked on a number of Q Tips, a few of those softer wooden toothpicks, and one of those plastic kind of toothpics that has one side as a kind of a little plastic sword (one edged) and the other side like a brush (I used the sword side, as it is soft and doesn't scratch coins).

Putting the coin under a microscope and slowly removing the material -- slow and steady wins the race

-- and the coin came out very nice.

When done removing the paste like substance with Blue Ribbon as the liquid to loosen it up, I then rinsed in Acetone and then filtered tap water for about 30 seconds

mercurydimeguy · October 5, 2005 10:28AM

Got the coin back from PCGS today -- here's what it looks like:

xbob · October 5, 2005 11:05AM

You did a fine conservation job! Nice coin. The clash wasn't even visible in the TT photo.

I had a crud experience of my own a while back - but the coins were very far gone and far from valuable. Link

A question about removing some surface material from a coin

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