Using Potassium cyanide to clean silver coins

ambro51 · January 27, 2008 12:31AM

OK wowwee I know this will get tons of "dont" posts but let me say first I am an alternative process photographer with extensive experience in using this chemical.

1/4 gram of KCn in water, put in the tarnished clouded silver coin and it dissolves the layers of scum in an instant.

Yup I love toning and wont advise anyone to remove it, I done this just as an experiment on a generic Morgan.
This is the way the old time collectors cleaned their coins.

Coinlearner · January 27, 2008 12:33AM

......"Don't"

ambro51 · January 27, 2008 12:34AM

Yeah, DONT. I concur, it was just an experiment, and I am qualified to handle the chemical

planetsteve · January 27, 2008 12:43AM

<< OK wowwee I know this will get tons of "dont" posts but let me say first I am an alternative process photographer with extensive experience in using this chemical.
>>

Hmmm... I bet you have a whole 'nother world of uses for platinum and palladium, too.

I seem to recall that cyanide is less likely to give a coin a dipped-out appearance -- any truth to this?

How does Joe Hobbyist get access to these chemicals? (Might as well PM me if a dozen nervous nellies show up on this thread.)

AUandAG · January 27, 2008 12:45AM

How is the luster effected? Do you have pics? If it works well I'd be happy to send you
some ugly toners.
bob

ambro51 · January 27, 2008 12:51AM

I left my camera at home this morning so cant photograph till after lunch. I done an 1898 morgan which was just scummed with haze and a tiny bit of toning, not pretty at all.

It restored full luster and cartwheel gloss and cleaned into the lettering etc. Very effective,

KCn is commercially used in most metal plating and in refining silver and gold. Small quantities WERE available through Artcraft Chemicals in Schenectedy NY but he is no longer carrying it due to requests from lovelorn teenage girls. KCn is a reducing agent for silver salts as well as mettalic silver, though it takes MUCH longer to work on the metal itself.

planetsteve · January 27, 2008 1:23AM

<< KCn is a reducing agent for silver salts as well as mettalic silver, though it takes MUCH longer to work on the metal itself. >>

Does this property mark an advantage over other reducing agents?

ProofArtworkonCircs · January 27, 2008 1:27AM

I remember reading a piece about a prominent US numismatist in the WWI era that was going to give a speech to a Bristish numismatic society. He was going to present a silver coin to them and was cleaning it with cyanide in a glass. He was also drinking a glass of ginger ale simultaneously. That is how his body was found.

ambro51 · January 27, 2008 1:29AM

It certainly does in the refining world.

We use it in place of Hypo in wet plate photography becuase it give a cleaner deeper black in the image, without the browning effect of hypo, which contains sulfer.

ProofArtworkonCircs · January 27, 2008 1:31AM

Ambro51 is your monicker in honor of the ambrotype and your profession?

ldhair · January 27, 2008 1:42AM

This was bought at a major auction years and years ago.
It was said to have the look of an early cyanide cleaning.
I don't know if that is right or wrong.

Mark · January 27, 2008 1:44AM

ProofArtworkonCircs:

The collector was Sanford Saltus, a famous American collector. He died in a London hotel as you describe. The ANS has an award named after him because he was a generous donor to the ANS.

BAJJERFAN · January 27, 2008 1:51AM

Of course use a fume hood and don't lick your fingers. Is cyanide a reducing agent or does it really form the soluble complex Ag(CN)2- ?
The fact that cyanide would reduce ionic silver to metallic Ag(0) doesn't exactly jive with its use as a large quantity leaching agent in lagoons of silver or gold residues.

Arizonadesertrat · January 27, 2008 1:53AM

KCN (and NaCN) will be much more difficult to obtain in the future---both have recently appeared on the anti-terrorism standards list put out by the Dept. of Homeland Security. Both are quite dangerous, even at near-neutral pH, because the protonated form (HCN) is a gas that shuts down cellular respiratory metabolism. The end result is death by heart failure.
If you don't have significant experience with hazardous chemicals, reagents like KCN are very dangerous to use anywhere.

ricko · January 27, 2008 1:53AM

This does work very well... my only reservation is what effect it has in the future... A very good neutralizing rinse would (IMO) be mandatory to prevent future toning of an 'unnatural' appearance. Cheers, RickO

fcloud · January 27, 2008 1:55AM

Ah, the creation of a new coin doctor.

Please perserve the history of coins without wrecking them. Buy stuff you like instead of creating it. It may look great after you do it but in the long run it will be ruined.

TomB · January 27, 2008 1:57AM

Seems like a whole lot of risk for nearly no reward.

ambro51 · January 27, 2008 2:14AM

I know I know I know I know I know

Im just passing on this little tidbit of info. There are four fatal doses of cyanide in one gram. It is *NOTHING TO MESS WITH* if you dont know what you're doing. I do, however, know what Im doing with it. The main concern with any cyanide soloution is to NEVER let any acid interact with it. The gas that arises is extremely toxic. Early photogaphers frequently had missteps with their fixer, by an amazing chemical coincidence, the developer, which is a mildly acidic soloution of ferrous sulfate, was the antidote. By an odder circumstance, today the antidote for cyanide poisining is an injection of sodium thiosulfate....the *other* fixing agent in photography

I **REALLY** dont want to advise this, or suggest doing it, Im just passing out the info.

BillJones · January 27, 2008 2:16AM

I've seen coins that were cleaned this way, and they shout I'VE BEEN CLEANED!!!!!!!!!

One word DON'T.

BAJJERFAN · January 27, 2008 2:25AM

Can one still get it from the Jim Jones Kool Aid company? I'm told by our ES&H manager that we have had customers over the years who have ordered it for the express purpose of doing the dirty deed to themselves.

Broadstruck · January 27, 2008 2:33AM

Just a few old time numismatists who confused cyanide with a sparkling glass of refreshment while dipping coins.

TwoSides2aCoin · January 27, 2008 2:38AM

The only thing I clean that is remotely close to a coin is my loupe. But thanks for the chemistry lesson

Weather11am · January 27, 2008 2:43AM

Hmmm...some chemistry, potassium cyanide dissoved in water is:

KCN yields K+ (aq) and CN- (aq)

Right? It is not a complex right?

NumisOxide · January 27, 2008 2:44AM

I think I remember reading something about some old time collector or dealer that died by accidently drinking cyanide because he confused it with his nearby glass of ginger ale. It might of been in the photograde book by Ruddy.

I just looked it up and found it in this NCS article:NCS Article

greghansen · January 27, 2008 2:45AM

I'm happy to say, my curiosity is not the least bit aroused by this information. In the hands of a properly trained person and with the correct safety measures, this may have some utility for those who seek to conserve certain coins. I'll happily leave it to the professionals to sort it out.

BAJJERFAN · January 27, 2008 3:25AM

<< Hmmm...some chemistry, potassium cyanide dissoved in water is:

KCN yields K+ (aq) and CN- (aq)

Right? It is not a complex right? >>

Silver ions complex with cyanide!!

UTTM07 · January 27, 2008 3:27AM

Keyword is silver ions. Dipping in cyanide or ammonia simply complexes the oxidized metal ions and dissolves them in solution. This leaves the unoxidized metal atoms intact. As long as the toning isn't too thick and you don't leave it in the solution too long, it should be fine.

jmski52 · January 27, 2008 3:36AM

today the antidote for cyanide poisining is an injection of sodium thiosulfate

Somehow, I just don't believe that I'd enjoy this..........

tincup · January 27, 2008 3:39AM

I'm amazed that this is even being discussed as a coin cleaner. In my opinion, anyone would be a FOOL to even consider this, when there are sufficient other methods out there. I also have somewhat extensive chemistry experience.... and this is not something to mess with. There is NO lee way for ANY errors....

It is true that cyanide gas is given off with any addition of acidic solution into the dissolved cyanide solution. One breath of this gas will be all it takes.... you will have just about enough time to know that you screwed up.....

If you have a solution of that cyanide compound, and somehow spill some of your ginger ale or cola into it.... the gas will be released (these drinks are acidic).

If I recall, cyanide gas was what Xylon B? was, in the days of Nazi Germany.

Weather11am · January 27, 2008 3:42AM

So its (Ag2CN)- complex?

BAJJERFAN · January 27, 2008 4:36AM

<< So its (Ag2CN)- complex? >>

I believe that would be correct tho properly written as Ag(CN)2- You may wish to consult Cotton and Wilkinson just to be sure.

291fifth · January 27, 2008 4:38AM

Find another alternative process that doesn't use that chemical. Too dangerous to fool around with.

Weather11am · January 27, 2008 4:48AM

I got it, the Ag is + and each CN is -. So its Ag(CN)2 -

BAJJERFAN · January 27, 2008 4:51AM

<< I got it, the Ag is + and each CN is -. So its Ag(CN)2 - >>

jhdfla · January 27, 2008 5:03AM

If I recall, cyanide gas was what Xylon B? was, in the days of Nazi Germany. >>

Zyklon B, an insecticide which released hydrogen cyanide when the crystals were exposed to the air. Ironically developed for pest control by a German Jew in 1933.

firstmint · January 27, 2008 8:30AM

A few words of advice if you decide to use this for cleaning gold or silver coins...

Make sure the room is WELL VENTILATED.

Make sure to wear RUBBER GLOVES (or your fingers will turn brown).

Dont leave any other containers open.

Flush down the toilet when the solution becomes cloudy.

Keep it away from all other persons.

Broadstruck · January 27, 2008 8:33AM

Past brown fingers if absorbed it will damage some internal organs... think it affects your Liver?

Awe the price of white coins!

planetsteve · January 27, 2008 8:35AM

<< A few words of advice if you decide to use this for cleaning gold or silver coins...

Make sure the room is WELL VENTILATED.

>>

I was thinking that a laboratory fume hood would be the only way to go (lest anyone here believe that I really am crazy). I don't have any coins -- short of moderns -- that I would have any interest in dipping, but my curiousity remains: is this in some way a better reducing agent than contemporary alternatives?

Does NCS use cyanide chemicals?

oxy8890 · January 27, 2008 8:35AM

Has anyone tried weapons grade Plutonium to clean coins!?!

sweetwilliet · January 27, 2008 8:42AM

Read page 91, "A Deadly Misadventure In Coin Cleaning" in the Official Redbook of Morgan Silver Dollars, by QDB.

planetsteve · January 27, 2008 8:48AM

<< Read page 91, "A Deadly Misadventure In Coin Cleaning" in the Official Redbook of Morgan Silver Dollars, by QDB. >>

Thanks -- just did that. Rather dreadful that Saltus had allegedly purchased the KCN just one day earlier.

Interesting to me is that the reporting of the day said that KCN was reputed to "have the desired effect when other methods fail," but QDB goes on that the compound was "used to remove tiny hairlines and scratches, by etching away a few microns of the metal surface" (my emphasis). If that's entirely correct, then that's not exactly what I'm looking for.

coinman420 · January 27, 2008 9:02AM

i use a cyanide cleaner daily at work(electroplating) that is called a "periodic-reverse" that uses DC current which changes from + to - every few seconds. i would never dip a coin i care about in this as i think it would be too harsh. i`m not sure about the OP`s concentration but it may be weak enough to not harm the coin. just don`t lick your fingers

DoubleEagle59 · January 27, 2008 9:04AM

Come on everyone...

is the risk of using this hazardous stuff really worth improving your coin for a few extra dollars?

if I was the OP, I would have never posted this info.

ambro51 · January 27, 2008 9:13AM

I posted this as an informational piece. I know damn well none of you fellows can get ahold of Potassium Cyanide.

However, I am qualified and experienced in its use (though not in the coin field) and just though it would be an intersting tidbit.

You know, you are all at a much greater risk of calamity every day you sit behind the wheel of your auto.

So, case closed. BTW I know personally at least two dozen individuals who do alternative process photography using this chemical as a fixing agent and have had no ill effects or misfortunes during the past decade.

sorry sorry sorry sorry

I will and say 1000 hail marys and write 100 times "I will not post informative yet useless tidbits of information on message boards which are inhabited by gentlemen with a lot of free time and an active imagination"

I love you all.......Never meant this to get out of hand.

drwstr123 · January 27, 2008 9:15AM

Not too long ago I had to get rid of 8 lbs. of PC pellets. Shoulda seen the look on HAZMAT. Mike

charley · January 27, 2008 9:17AM

Respectfully, " I know what I am doing" = Custer, Nero, Marie Antoinette, King George, etc., etc. I am somewhat concerned about all the YN readers. I am cognizant of the many warnings posted, but still... might we follow the Hippocratic Oath- first rule- in regards to this Thread? Regards, John Curlis

TomB · January 27, 2008 9:18AM

Actually, some of us can get potassium cyanide very easily, but none (hopefully) would use it for dipping coins.

ambro51 · January 27, 2008 9:24AM

WOW

coinman420 · January 27, 2008 9:24AM

i saw no harm in your post. to me its the same as handling any other chemical or solvent.

LeeG · January 27, 2008 9:29AM

A person who wishes to do harm, will find a way, no matter the results to themselves or others. As intelligent human beings, we wouldn't use this, or any other chemical, to clean coins that we have no knowledge of. And I repeat: A person who wishes to do harm, will find a way, no matter the results to themselves or others.

Bear · January 27, 2008 9:40AM

The only things collectors should use are

Olive oil for copper, MS-70, Acetone and

distilled water.

Usually, folks that are all knowing, are usually the

very folks that poison them selves, shoot someone

have car accidents or drown while swimming during

dangerous conditions.

Using Potassium cyanide to clean silver coins

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