What is this white gunk? AFTER pictures added and don't do stupid stuff.

Stork

Bought a coin on eBay, bad pictures and the coin is actually pretty decent, except I can't figure out what this white gunk is. First pass in an acetone bath had no effect. Currently soaking in acetone.

Anyway, any ideas on what the crud is? The combination shot is the normal look. I took the detail shots and cranked things like contrast and saturation to make it a bit more obvious. And, if it doesn't come off with acetone, what next? Is it worth trying something else like Coinserv or MS70? Professional conservation? (not cost effective, but I like the little guy)

harasha

When I was a little boy and got coins, I sometimes washed them in soapy water. The gunk could be soap residue.

WillieBoyd2

I would scrape it with a toothpick and see if it comes off.

I recently found a modern coin in a CoinStar bin and boiled glue off of it.

pruebas

I had this on coins before. I think it's clay or something similar with which someone made an impression of the coin.

It's harmless but ugly (IMHO).

The only way I know of to remove it is mechanically (toothpick or similar).

Stork

I'll give a toothpick a try. It does look like a clay or residue.

syl

I've seen people clean coins with toothpaste .. use a thorn or toothpick to remove.

harasha

Toothpaste can contain abrasives. I would stay away from that method.

Stork

Well, no toothpicks in the house. I'll pull it out of the long acetone soak, but I've got a work weekend starting tomorrow and will put off the project until next week. I'll avoid the t-paste for now. If it's clay or soap it should help.

TomB

I've seen this on more than a few RE half dollars (1836-1839) as well as some CBHs (1807-1836). I don't know what it is, but it always seems to appear on coins that are otherwise problem-free or original. I have even submitted more than one to PCGS and never had a coin kicked out of grading because of it.

Sapyx

If it's just regular mud, or something similar (like plaster of Paris) try a soak in plain old water.

lordmarcovan

Wax, maybe?

No toothpicks, you could always use a bamboo skewer or rose thorn.

syl

I didn't mean to actually USE toothpaste .. only that I've seen some people ruin coins by using it. I use hawthorne thorns to pick any gook/grundge out of the recesses. Longer and stays sharp much longer than a rose thorn. Find a friend or city tree that has a hawthorne and you'll be glad that you did.

Stork

Gotcha! Okay, so look for a Hawthorne tree.

@TomB--did they slab them anyway, or did they remove before slabbing? I don't think this one is headed for a plastic tomb, just curious.

brg5658

I'd agree with the others that it's a relic of someone having made an impression of the coin. I've seen a decent number of coins with left over wax from making impressions (common in the 18th and early/mid 19th century). They also sometimes used tin/foils to make impressions.

Below is an interesting excerpt from the 1771 Encyclopaedia Britannica (p. 57) on Impressions of Medals:

asheland

My first thought was also to use a toothpick gently.
Nice coin!

ShadyDave

That looks like wax to me. I'm not sure if acetone will dissolve wax or not...

FellintoOblivion

Try heating the coin up, that will reveal if it's wax.

I use a hair dryer to heat up the metal on guns when I apply colored wax to engravings, that should be hot enough for a coin.

Stork

After an overnight in acetone there was no change. The more I think about it in hand, the more it does resemble a wax.

I don't know about a hawthorne or a rose bush, but I do have a nice bush in my backyard that has green thorns...long and poky but still a bit flexible this time of year. Those should work.

The hairdryer idea sounds great too. If it does come off it will be interesting to see what kind of difference there is in the toning. I do hope the hairdryer works or this could be a long an tedious process.

Well, I'm stuck at work and the soonest I can try is on Monday.

Great thoughts and ideas!

MacCrimmon

When 1jester was selling his collection I handled a portion of it through eBay. He had a couple of 17th and 18th c. European gold coins which had what appeared to be red wax in the crevices, etc. As I recall acetone was not very effective, but one of the old copper guys suggested trying a dab of xylene. So I tried saturating a Q-tip in the xylene and gently pressing, or rolling into the waxy area .............................. and POOF!!, it vanished. Well, I presume the xylene "melted" the waxy substance and it was absorbed into the cotton end of the swab.

CAUTION!!!!! Xylene is a nasty solvent Pay attention to the SAFETY precautions in the Wiki link. https://en.wikipedia.org/wiki/Xylene. Note the bit about industrial uses and PARAFFIN

Do it outside, away from flames, and/or electrical switches. Also, be sure the wind is blowing away from you, i.e. do not inhale. The coin is your patient, so wear an ER mask, too. You can get a can of xylene (xylol) at an Ace Hardware, Lowes, etc.

Good luck.

Michael1

It looks like a mug or glue. You can try to clean this coin with soap and warm water.

bkzoopapa

I have this on coins that were cleaned with silver polish paste

Stork

Well, I still haven't gotten around to it yet...thankfully I doubt it's a polishing paste as the rest of it does not appear to be scrubbed. I'm still working out how to do this--this may require a bit of magnification with my eyes/glasses so I might have to try setting it up under my camera and using the thorn using the Live View feature on the software. Once it gets done photos will be posted.

RobP

It is probably grease in this case. It could easily be finger grease or maybe someone has lightly greased the coin in the past to preserve it.

In the case of the red wax, please do not remove it. It is wax residue from impressions taken in the late 19th and first half of the 20th century for catalogues, printed articles or for a museum to make a cast. See that and you know it was probably illustrated somewhere. Although there are services offered in the US to remove this 'unsightly mess', all they are doing in fact is removing historical evidence through cleaning.

RobP

I agree it could also be polishing paste residue.

Insider2

@Stork
White residue like this is usually paint, baking soda, or polishing rouge. It does not look cleaned or polished. The first thing to do is soak it in water. Than, sharpen a tooth pick with a razor blade and see if the deposit is soft (it will move) or hard (it won't move UNLESS it is hard and very brittle). In that case you can continue to push it off. Note: Conservation like that is done using a microscope so the coin is not scratched. Acetone would have removed anything organic. Wax can be pushed off, even when hard. Use a hair dryer to heat the coin and see if the substance moves. Don't burn your fingers as only a little hot air should work. Try some paint remover on a Q-tip next. Don't rub it on the coin. Dab it on one spot to see what happens. Do it several times on the same spot and then see if the substance moves. Goo Gone removes stuff too. White jeweler's rouge is soft and will push off.

Please let us know what happens.

Stork

Hmph. I should have tried things in a different order and used my head a little bit....

So, soaking in acetone did nothing.

Got some nice long thorns.

Bought some xylene and mineral oil (different thread advice).

Figured I'd try a mechanical removal first.

The soap and water idea actually made sense too.

BUT, did I stop and use my head? OF COURSE NOT. I decided why not combine the soak and the soap and use some softsoap...you know, the kind with scents etc. (roll eyes and btw this is the ingredient list for softsoap-- Water, Sodium Laureth Sulfate, Cocamidopropyl Betaine, Decyl Glucoside, Sodium Chloride, Fragrance, DMDM Hydantoin, PEG-120 Methyl Glucose Dioleate, Tetrasodium EDTA, Sodium Sulfate, Polyquaternium-7, Citric Acid, Poloxamer 124, PEG-7 Glyceryl Cocoate, D&C Red 33, FD&C Blue 1).

Note to self--next time use SOAP OR MINERAL OIL. Don't try to use a shortcut. Really. Don't.

So, I left it in the soap for a bit and this is what I see:

flip it over

I did NOT expect to see all that green stuff coming off. I also noted an improvement in the muted luster the coin initially had, but that could have been the soap. Still, that was an awful lot of greeny stuff that had not come off after a prolonged acetone bath so I sincerely doubt it was pvc..but it was something.

Next I used my thorn to mess with the white gunk. Contrast cranked a bit. Gunk was turning to goop and was notably moving even before I started:

a detail spot

getting messed with

Then THOROUGHLY rinsed in the hottest faucet water, and rinsed off a final time with acetone.

Here is the after shot using my typical set up including lighting. (I didn't waste time getting ALL the gunk off...a lot came off on it's own and I did a lot with the thorn. I saw where this was going and didn't bother with all of it as frankly it was kind of boring and the coin is not that valuable...and under the white gunk was not damaged so it wasn't pressing to get it all off).

I was however disappointed in the final appearance--might as well as dumped it in MS-70 I suppose. Something more than the white gunk came off without a doubt. A bit more luster can be, but the muted look was actually more pleasant--and the field chatter less obvious.

Next time, skip the softsoap (facepalm) and either do a real soap and water trial or just let it soften up in mineral oil before the mechanical efforts are initiated.

It was a good experience in learning the thorn technique. I used my camera on live view and looked at my computer monitor which worked pretty well once I learned to compensate for the offset view. Not too hard.

I like the thorns out of my backyard, long and skinny and you can take a bit of branch to use as a handle. If I ever have to spend a long time at it I'll set up an audiobook for entertainment too

The mineral oil I can save for the next trial, but now, what am I going to do with a can of xylene...

ChangeInHistory

Nice improvement, good informative post too.