Restore Silver with Electrochemistry 2017

Restore Silver with Electrochemistry 2017

Greetings fellow nerds. In this video we’re going to restore tarnished silver using electrochemistry. First i need to issue a warning to any silver collectors, coin collectors or antiques dealers. Artificial chemical alteration of silver is very poorly received by the collector community in general. Do not perform this on any pieces that have any historical, numismatic or other value beyond the spot price of the silver metal itself. Our objective in this video is to explore the science. Anyway I made s silver restoration video back in 2009. I personally really liked it and have always wanted to redo it but using a modern 4k resolution camera as opposed to the really low end 720p camera i had back then. So let’s get started restoring silver by electrochemistry in 2017. So first we need to make our restoration solution. We start with 200mL of water and add to it 20g of table salt and 10g of baking soda. Stir for about 5 minutes. It won’t all dissolve but that’s acceptable. It also helps to heat up the solution so it works faster during the restoration step. Now get a shallow tray with some aluminum foil and pour in our restoration solution to cover it. This actually works best with an all aluminum tray but i’m using foil so i can show you the chemistry. Let me zoom in for a better look. And here is our badly tarnished silver coin. Technically it’s a silver round but the chemistry is the same. Now putting it into the solution by itself nothing will happen. We need an electrical connection for this to work. So let me put it on top of the aluminum foil to connect them. And there we go. I’m not timelapsing this. This is really happening that fast. And that is our restored silver coin. Let me do it again this time with a deeply tarnished silver coin. This will take a lot longer but it will still work. So what’s happening? The colored tarnish on the silver is actually silver sulfide formed by reaction with small amounts of hydrogen sulfide and oxygen in the air. In the solution we set up a basic electrochemical cell. The aluminum foil is the anode and is oxidized in the alkaline solution releasing electrons. Normally these just go to making hydrogen gas but if we touch the silver to it then the electrons go into the silver. The silver behaves as the cathode and reduction occurs. The silver sulfide is converted back into silver metal and the sulfide ions go into solution. Overall we’re transferring the sulfide from the silver to the aluminum. Now this works so well with aluminum because it has a much lower reduction potential than silver sulfide. So it’s strong enough to force the back reaction of converting silver sulfide back into silver metal. So you might be asking what would happen if we tried a metal other than aluminum. Let me try again this time using nickel metal. Nickel has a much higher reduction potential than aluminum. In fact it’s even higher than silver sulfide so as you can see nothing happens. The oxidation of nickel just isn’t strong enough to force the reduction of silver sulfide. Let me try it again now this time using a strip of nickel in which we’ve plated zinc metal. The upper end of the stripe is still nickel metal. Now zinc has a lower reduction potential than silver sulfide so this should work. But to make this experiment more interesting i’m going to put the tarnished silver on the nickel end. Interestingly enough it’s still working. This emphasizes the electrical nature of this experiment. The zinc is being oxidized by the solution as usual but the electrons travel through the nickel strip and into the silver where the reaction takes place. The nickel itself doesn’t do anything but is the conductor for the electrons. Now let’s take this a step further. If this is all about pushing electrons, then we should be able to force the reaction forward with a battery. A battery provides its own power and can push reactions that aren’t favorable on either electrode. So here i am zoomed in onto a heavily tarnished coin and i’m attaching the negative terminal of the battery to it. Now all we need to do is touch the positive terminal to the solution and complete the circuit. The battery will rip electrons out of the copper wire and force them into the silver. This should be much faster since we’re using a six volt battery pack. Far greater voltage than the lowly 1.6 volts of the aluminum. Ready. 3..2..1.. That was over in less than 2 seconds. Let’s see that again. Interestingly enough the reduction wave starts nearest the positive wire, the anode, and moves away. Even if we do it on the same side the effect is dependent on the anode wire position. This is because the silver sulfide closest to the anode is the most strongly polarized and is reduced first. Once that’s reduced the electrons go to the next most easily reduced silver sulfide which is slightly less polarized a little further away. This effect repeats and gives us this wave. So that was the restoration of silver using electrochemistry. I hope you enjoyed my video. And let me know if you think i should redo any other old video in modern high quality. Special thank you to all of my supporters on patreon for making these science videos possible with their donations and their direction. If you are not currently a patron, but like to support the continued production of science videos like this one, then check out my patreon page here or in the video description. I really appreciate any and all support.


  1. That was EXTREMELY cool. I had no idea this was a thing, thank you, as always, for your informative and interesting content!

  2. When you say the electrochemistry is the same between coins and rounds, are you aware that coins contain 10% copper?

  3. 720 with 10bit colors(1024 shades of each channel) and less compression, beats most consumer "4k" which is only 8bit color to start(256 shades each channel) and then 3/4 of the color info is discarded in the 4:2:1 sampling followed by obscene lossy compression and artificial smoothing to make all the compression artifacts less obvious to the casual observer(while loosing even more of the original image information).

    In short, there may be 4k pixels displayed for marketing but the image doesn't retain anything close to 4k of optical resolution. ie I can display one big single color rectangle using 8.3 megapixels(4k) and legally sell it as a 4k picture even though it is in optical reality only one pixel of information, possibly even one one bit color depth(pure black and white, no grays)

    Even with raw data though most cameras have enough lens and sensor noise that 4k offers little realized resolution gain over 1080. To get true 4k image resolution requires multi-thousand dollar lenses and sensors.
    Then you get to brightness range and such which makes a huge difference in scenes with for example a dark room and bright window. Full professional cameras capture lots of extra information not because it can be seen with the eye in as shot form but because it allows better processing after the fact if color and brightness curves need to be adjusted. Say only the lower 1/4 of the sensor sensitivity range was used because of lighting constraints, you expand that part of the curve(brighten the image) to cover a normal looking overall image brightness, well now with an 8 bit camera you are left with 6bits(64 shades per channel) without artificial interpolation and would likely have obvious banding[contouring], if you started with 10bit you would end up with a standard 8bit channel depth.(most pros can actually do 12 or 14bit) Banding (also known as posterisation and quantification noise) example

  4. Was about to complain the coin will worth more if u keeps its original looks, then your shutter me up by putting the disclaimer at start of the video. )

  5. Wow, the wave effect across the coin was a big surprise. My guess would have been that it would be much faster.

    However, I think there is more than meets the eye here; if it is just electrons (and maybe just ions), you might think faster, instantaneous. So what's going on; are the ions slower than I guess, is there a secondary reaction occurring, is there some-type of kinetic effect?

    Any thoughts.


  6. We have been using this to clean silver ever since in our household, but we only used salt, no baking soda and it worked fine too, does the baking soda really make such a big difference?

  7. I tried this while back to clean tarnished silver dimes (90%Ag 10%Cu) (instead of toothpaste) but didn't work. I ended up with copper cladding the coins along with Al foil stuck to them.

  8. That is very educational video. It will also make people better understand why steel does not corrode when coated with zinc layer or in contact with a zinc object. Your example is so fast that it is much easier to observe than slow steel corrosion process.

  9. Thank you! I just cleaned 15 years of black sulphide from our teapot using this method in a bucket. It worked brilliantly while I found I could 'encourage' the process by rubbing the stubborn parts with bicarbonate powder.

  10. How is the wear on the silver using this kind of restoration compared to silver polish? Does one of them cause more long term wear on the silver than the other?

  11. hey, +NurdRage You should make a napalm video, I have seen everyone on YouTube do it, but I have never seen anyone do the Sodium Hydroxide method which is the actual method. It would be interesting to see, I have seen your gelling alcohol video, but not sure if I've seen you do a napalm video.

  12. Thanks man did this to my mothers silverware set, she was so happy to not be using a rag and buffing compound, did a full set in like 5mins, although she wasnt to happy with the smell of the kitchen afterwards.

  13. Would this work the same for 925 silver? (commonly used in jewelery) or would it have some other kind of reaction since that silver isn't quite so pure?

  14. Really cool! I did this on silverware using a 9V battery and copper wire. As can be seen also on your video, some blue stuff forms on the positive wire. Is it copper hydroxide? I did this on a stainless steel tabletop and also noticed afterwards that two small marks had appeared from somewhere. Could it be something related to this?

  15. It was taking to long to shine one of my bugles so i tried this though i used a method similar to brush electroplating, Its amazing how fast the reaction was. Instead though i used a 9v battery not a pack

  16. NR you have to stress in your video that this only works with 100% pure silver coins.
    I tryed this on my 68% and 85% silver coins and absolutly NOTHING happend.

  17. What would happen if you left the wires attached to the battery pack for say an extended period of time? The silver changed in around 2 seconds, which was glorious, but what would happen that coin if you did it for say 20 seconds? Or 2 minutes? Would you see a noticeable build up on the coin?

    Thank you in advance.

  18. Can this be used to make a battery, like using the solution as an electrolyte, aluminium as a reductor, a paste, like let’s say Iron oxide, and a lead electrode?

  19. Even being well aware of the "patina"-nazis, I am still very surprised about the information in your warning. If they interpret that removing tarnish in this manner is somehow deceptive, then that just blows my mind. But maybe you just mean that removing the tarnish kills the value. If so, I can understand that. It's ridiculous, but I can understand it. If you have the right chemicals, and do the right process, you can speed an aging effect in such a way that is totally undetectable. Patina is not an attribute that should be used for the sake of price estimates! >_<

  20. Video was playing in 720 and when I heard you recorded it in a higher resolution I went to the highest I could, that being 1440p

  21. So how do you tell if this has been done to a silver coin that way if you’re a collector you don’t buy one that has had this done to it reducing the value?

  22. My mother once restored her heritage silver spoons, forks and knives by just boiling them in an aluminum kettle, using just a small amount of ordinary (iodized) table salt in also small amount of our quite hard tap water. The silverware had been tarnished due to little use and no protective paper wraps or anything. Previously they had been occasionally cleaned by some mildly abrasive paste, but that was tedious, one piece at a time. Moreover it removed some of the precious silver. This salt and aluminum method was in effect a bulk operation and also did not consume any of the silver.

  23. Wow, your video was very well done, and more informative than I could handle! Thank you.
    I've a question that lead me here in the first place, perhaps you could help:
    I was wondering if something similar would work on a carbon steel knife. Carbon steel oxidizes forms a patina when it comes in contact with moisture, and even more so with acidic elements. I've often used baking soda mixed with only a few drops of water as a slurry to rub deeply against the steel and thus remove the patina.
    Would iron steel enjoy the same process that silver does? Perhaps some metal "lower" than aluminum?
    Did this make sense?
    Thank you for your help!

  24. I just did this experiment today, and it is amazing. I use it to clean some of my wife's expensive toys and it worked so nice. I did a small alteration that did increase the reaction speed, a few seconds on the microwave 😀 that resulted on a reaction as fast as the electrolisis process

  25. I'm about to ask a dumb question. It is because I have high school level understanding of chemistry and unable to figure this out for myself. The question is what would one need to reverse bronze in this way, and copper. Let's say I have Penny's that I want to make look new again just for the sake of education. What would change? Could I use this exact method or would I have to change out my metal for my anode? The penny would be the cathode correct?

  26. I wonder if this is an alternative way to validate your silver.??? So, if it's real silver , this will work. If it's not silver then and will not work????

  27. Yesterday i was In a mineral bath and my silver pendant stained itself instantly, this vid Will be realy useful.

  28. Hi,
    I was very excited when I watched the video. I work a lot with silver and tried the method with the batteries today. I used a 9 Volt battery and tried it on a spoon. I used cables with crocodile clamps. It was heavily bubbling and the water turned almost black which got me thinking it works for me too. However: The spoon is still dirty but the positively charged crocodile clamp fully dissolved in the water! What did I do wrong if so?

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