How to remove solder from gold jewelry and coins

A. Hi Emily. Solder has a low melting point, which is the reason it is used. So the wires and the bulk of the solder can be removed by melting with a small soldering iron and sucking it up with desoldering braid or a solder sucker. You can get what you need from an electronics store for about $25.

However, this will leave an unsightly thin coating of solder on the coins which must be chemically dissolved with a stripping solution probably incorporating hazardous ingredients like ammonium bifluoride. I would probably want to entrust that to someone who has both chemical stripping experience and jewelry expertise like Metal Arts Specialties or Red Sky Plating [a finishing.com supporting advertiser]. Hopefully the solder can be removed without substantial dissolution of gold.

I would not at all be confident that those gold coins are real, though, unless you have strong reason to think so. The overwhelming majority, virtually all, are just plated with a layer of gold so thin that it has essentially no value. Good luck!

A. I would soak them in hydrochloric acid [muriatic acid ⇦this on eBay or Amazon [affil links] ], heated to work faster. The acid will not touch the gold but will dissolve the lead and tin. You may have to soak it, rub it with a soft cloth after rinsing off with lots of water, and put it in acid again. Repeat until all the solder is gone.

  Thanks, Frank. Readers should note that hydrochloric acid is a hazardous material. I don't think it dissolves lead, but assuming the lead content of the solder is low enough, it might work.

Regards,

A. You can use next solution:
acetic acid ⇦this on eBay or Amazon [affil links] (conc.)...........24%
hydrogen peroxide (30%).....4%
water.................72%
0,2-0,3 mm/per hour
Good luck!

A. You can remove lead from silver or gold by using a mixture of nitric acid^ ^{[ed. note: we believe this to be an error; be sure to read entire thread!]} and hydrogen peroxide.

A. Hi, Jill. It's readily available from jewelry supply companies, but they can be reluctant to sell it to people who don't have some kind of environmental certification and an actual industrial/commercial jewelry store (outside of the home) because of the liability of product stewardship. It's dangerous toxic stuff, and moreover a very powerful oxidizing agent that can start fires.

A friend tried to sop up a nitric acid spill with newspaper and nearly set his whole shop on fire -- fortunately it was a very high ceiling steel ceiling building with a concrete floor. Had it been a house or wood building, he absolutely would have :-(

Regards,

Hi Peter. Goran gave the exact recipe for his idea. I don't know the ratio for Neil's idea, but thanks for including "non-ferrous" in your question, because it reminded me of still another warning about nitric acid. Don't even think about using it on steel or iron: it generates NOx-ious choking fumes if used on iron or steel.

Regards,

A. Hi,
I used a mixture of (50-50) hydrogen peroxide, or blonde hair dye and photochem econostop, the stuff photographers use, basically it's acetic acid , and it removes lead from gold.
regards Neil

Thanks readers, but we need some precision here! Nitric acid is a radically different chemical than acetic acid ! I have the strong feeling that Neil's original mention of nitric acid was in error! I'm not a photographer but my understanding of photographic stop baths is that they are acetic acid , so Neil's original posting was the one in error.

Regards,

A. Hi Ronald. I think the original posting about nitric acid was in error and nitric acid is not used in this operation. But unless you are a chemist with haz-mat training I would suggest that you not mix nitric acid with hydrogen peroxide anyway :-(
Internet forums are giant one-room schoolhouses which both grammar school children and post-doctoral researchers google themselves into, and reading that something can be done does not mean it can be reasonably or safely done by people not trained in it.

Regards,