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Jeweler wants to clean gold and silver using cyanide

Q. I would like to know the proper technique and use of sodium cyanide with particular attention to safe use in cleaning old tarnished gold and silver. I also would like to know where this type of cyanide is available or possibly you can advise me where this information can be obtained.


James Rose
small independent jeweler - Duluth, Georgia, USA

A. Don't even think about it! Unless you know what you are doing, you run the risk of killing yourself and your neighbours. Cyanide is highly toxic, that's why it is used in the gas chamber to execute people. Furthermore, disposal of unwanted cyanide will be a major problem to you - your local water authority will not be impressed if you tip it down the drain! I suggest you get a soft toothbrush (preferably a battery powered one) and some soft dental paste and carefully clean the jewellery that way - it's much safer and may make the jewellery smell nice too!

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK

A. James!

Why you want to use cyanides. I am sure that you know that cyanide is deadly poison. You can use acidified Thiourea [on eBay or Amazon affil links] solution (1 lit water/100 gm thiourea/ add phosphoric acid until pH is 1) or sodium thiosulphate [on eBay or Amazon affil links] solution(300 gm /1 lit water). For thin tarnish layer you can use precipitated chalk and water mixture ⇨
Good luck!

Goran Budija
- Cerovski vrh Croatia

A. Please note that thiocarbamide (thiourea) is a possible carcinogen.

Arsi Saukkola
- Espoo, Finland

A. I would suggest the dark web. You can bypass customs by ordering from a seller within your own country. Be safe, wear proper personal protection equipment.

William C [last name deleted by Editor in case it's fictitious]
- Burlington, Vermont
January 8, 2021

January 2021

thumbs down sign Hi all. Privacy is valuable and William is completely welcome to post from a Virtual Private Network (VPN) as he did. But then we can't even put his name here because there's no way for us to know whether it's real or fictitious -- and more importantly -- if some anonymous 3rd party is trying to get a real person in trouble :-)

Any metal finishing process distributor can ship cyanide, and they are happy to sell it to legitimate & qualified users. But the problem is that they try to practice good stewardship and generally will not ship it to a non-industrial location unlikely to have the equipment and training to deal with potential accidents.

Before following William's advice, you might want to review topic 4120 about a french chemist in prison for buying cyanide, or search the site for references to "Film Recovery Systems" whose managers were convicted of 1st degree murder when an employee died of cyanide poisoning, or "Bastion Plating" where six men died of cyanide poisoning. It's dangerous stuff.

The technique that James is probably looking for is "cyanide-peroxide bombing", and that one is dangerous even for those trained and equipped to handle cyanide. But searching the site with that term will reveal what's involved.

Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha - Pine Beach, New Jersey

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