Introduction: Polishing Silver the Easy Way - With SCIENCE!
Instead of polishing or acid etching off precious silver or potentially damaging set stones or other features on the items, we will use electrolysis to instead convert the tarnish (silver sulfide) back to silver metal!
I will demonstrate two different methods for doing this. In the first method, which works best on only lightly tarnished items, we won't even use a power source to perform the electrolysis, relying on the properties of two metals to pass ions between each other. In the second method, I will show how more aggressive cleaning can be done with a DC power supply, such as a 4 AA battery pack.
Once we complete the electrochemical conversion of silver sulfide to silver, we might want to remove surface scratches as well, in the case of items like jewelry, and for this I have chosen a Dremel with buffing wheels and compound, but you can use a jeweler's cloth as well.
What you will need:
Common for Both Methods
- Baking Soda (sodium bicarbonate)
- Salt (sodium chloride)
- Pitcher of Warm Water (heat increases solubility)
- Wooden Spoon (or similar, to stir water with)
- Large Non-Metallic Dish (Pyrex or glass recommended)
- Old Toothbrush or Similar Item
- Soft, Clean Cloth
- (Optional) Dremel or similar tool and accessories to buff the end result
- Tarnished Silver to be Cleaned
Simple Method
- Aluminum Foil (aluminium for readers across the pond)
Advanced Method
- Copper Metal (scrap PCB, pennies, plumbing scrap - will be damaged in process)
- DC Power Supply (4 AA holder with switch recommended)
- Alligator Clip Jumper Wires (optional - cathode may rust during cleaning)
Step 1: Basic Method
- Add a few tablespoons of salt and baking soda to the warm water and stir to mix it. This will help our water carry electrical current (even without batteries, we are utilizing electrical activity).
- Press the aluminum foil into the bottom of the glass dish.
- Pour the doped water into the dish, adding enough to completely submerge the aluminum and the item to be cleaned.
- Place the item to be cleaned on top of the aluminum foil, ensuring there is electrical contact between them. They should touch in a relatively clean spot.
- Watch as the aluminum gives up ions to the silver, causing the conversion of silver sulfide to silver metal again. In a little bit, your silver will be ready for cleaning with clean water, a toothbrush, and a rag to remove dislodged bits of dirt and oxides.
Once you wash the item, it should be shiny and clean again. If it has a lot of scratches from wear, buff it gently with a jeweler's cloth or use a rotary tool and buffing attachments to get it smooth again.
Step 2: Advanced Method
- Just like we did for the basic method, add a few tablespoons of salt and baking soda to the warm water and stir to mix it. This will help our water carry electrical current (even without batteries, we are utilizing electrical activity).
- Attach a piece of copper, preferably with a large surface area, to the positive terminal of the DC supply. I used alligator clip jumper wires. Place the copper in the bottom of the dish.
- Pour our doped water into the dish, adding enough to completely submerge the copper and the piece to be cleaned.
- Attach the negative terminal of the DC supply to the item to be cleaned. Again, alligator clips help. Submerge the piece to be cleaned, making sure it does not touch the copper, but is near it.
- Watch as hydrogen bubbles, dirt, and oxides are blasted off of the surface of the silver, and the tarnish becomes shiny silver once again.
If you want to remove surface scratches and restore luster, simply polish lightly with a jeweler's cloth or rotary tool.
Step 3: Conclusion and Results
We have successfully cleaned out jewelry in a non-destructive manner with amazingly little effort. As you can see in the attached images, this worked really well on some old and heavily tarnished jewelry. The largest ring with the big gemstone was restored as well, retaining its intentional patina in the crevices of the pattern but it looked so good when I finished that my mother-in-law swiped it before I could get a picture. Special thanks to Nurdrage for the inspiration behind this.
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26 Comments
Question 2 months ago on Step 3
Will that work with silver plated cutlery?
7 months ago
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12 years ago on Introduction
Hmmmm. Ionic Transfer.
Dont really need the wires and all.
I've used an aluminum baking pan, hot boiling water, and super saturated solution of baking soda.
just drop the silver piece in the solution and its clean as fast as that.
needs to be wiped clean with a soft clean cotton cloth.
Reply 4 years ago
they are lingy to you
Question 4 years ago on Step 3
In the "advanced" method, would it make sense to use a solution of oxalyc acid instead of salt or sodium bicarbonate? Oxalic acid is itself a reducing agent. I have been doing it this way, but with cold water and a bench power supply so I can control the voltage and current.
6 years ago
A project more ambitious-- my keybooard doubles letters, particularly the letter "o" (as you already may have observed), as well as othhers (h), etc. Theh doubling also involves a microsecondo of delay, as you note withh placement of the letters "h" and "o" within correctly typed but improperly displayed words.
My switch-based "clicky" keyboard (with full key depression) may have a switch prooblem, in which corroded mechanical switchh contacts improperly connect with each key depression. Yes, oof course, this malfunction may be due to a failled oor failing electronic/circuit board component in the keyboard, but I proceed withhh thhe simpler explanatioon, first (thank you William of Ockham)-- simple corrosion removal.
As a large obooject with 104 separate switches, immersion of thhe entire keyboard in a chemically-active cleaning soolution (unplugged from the computer) seems the most efficient remedy, since most parts are plastic. The keyboard hhas seen many years of service, but no mechanical abuse, since I am a fast but gentle typist. I suspect corrosion removal is all the keyboard needs.
6 years ago
Its a cleaning process not polishing,so you will need to polish it to passify the surface.
6 years ago
Yesterday I cleaned a silver sugar bowl with the aluminium foil process. It worked really well, and quickly.
Do you know if the same water can be used again? It became a bit cloudy. The aluminium foil seemed darker and 'delicate' (it tore easily). I guess new foil is used each time.
You'll probably be able to tell that I don't know much about chemistry!
7 years ago
I tried both ways. The aluminum method worked great. Then I tried the copper strip with a battery in the solution of salt and sodium bicarb. The silver turned copper and the copper turned dark orange in places and green in a very few places. I had the positive lead to the copper and the negative lead to the silver. Anybody know what happened or if it can be reversed?
Reply 7 years ago
Its called electroplating,
https://www.instructables.com/id/Clean-and-Simple-E...
Removing it is not simple, http://www.goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?t=13704
10 years ago on Introduction
I'm a professional silver restoration and conservationist. This process, known as electrochemical (Galvanic) Reduction, uses aluminum foil or an aluminum/ aluminum alloy plate and a warm solution of sodium carbonate (washing soda). When the object comes into contact with the plate in the solution, it removes only light tarnish, not the thick, black tarnish produced by years of neglect. Pitting of the object can occur if the aluminum plate is not periodically cleaned. Another not-so-obvious problem is scratching of the object when in contact with the plate.
Objects cleaned by this method may tarnish more quickly than silver that has been polished, for the object's surface will act like a sponge and more readily absorb tarnish-producing gases and moisture. The solution can also seep into hollow areas such as coffeepot handles, unsoldered spun beads around the tops of lightweight holloware, weighted pieces with minute holes, and any porous attachments. For these reasons, this cleaning technique is not recommended.
Visit my Web site for additional silver care information: http://www.hermansilver.com.
Reply 7 years ago
I have a silver tea set that has severe tarnishing. I have been using silvo polish to try and remove it but im finding it takes forever and I am using to my silvo. Do you have any recomendations for cleaning larger badly tarnished peices?
Reply 7 years ago
The above comment was 3 years ago, but I found an interesting compilation here from Readers' Digest http://www.rd.com/home/cleaning-organizing/how-to-clean-silver/ with some easy ways. I'm sure some have drawbacks which render them less useful for antiques and high value items but for quickly restoring a tea set to a shine, these tips should be fine. Of course, cleanse the set thoroughly afterward to remove anything harmful and residues which might tarnish the set all over if left on it. After that, it should just be routine maintenance. I hope this helps you. Удачи! :)
Reply 8 years ago on Introduction
While it is a Galvanic ReDox I'll refer you to the anodic Index table. Elements with more negative indices will be corroded leaving the other element relatively untouched. I'm also linking to the University of Wisconsin chem fun page which states that silver remains in place (reinforcing the anodic index corroding the aluminum). http://scifun.chem.wisc.edu/homeexpts/tarnish.html
I've never heard what you said about the silver becoming weakened though I'd like to learn more about that.
Have you been able to measure the concentration of silver in the solution by any chance? I'd be curious to see how much silver is in it per mass of silver.
Reply 8 years ago on Introduction
Forgot to post the link to the anodic index table! https://en.m.wikipedia.org/wiki/Galvanic_corrosion
8 years ago
I used this experiment for a science project and it worked perfectly! Thank you for posting! :)
8 years ago on Introduction
I have been using just this solution combo for all my silver fixes and it does work wonders! Baking soda and vinegar alone is already enough to perform mild cleaning but for an even thorough restoration, then this instructable with the aluminium foil is just what you are going to need.
8 years ago on Step 2
why copper rather than the aluminum? Is copper simply more efficient or will aluminum work as well if I have a big piece of scrap?
Reply 8 years ago on Introduction
Copper gives up ions more readily in this application and best results occur much more quickly. Aluminum is constantly coated in aluminum oxide and I think that interferes with the process.
Reply 8 years ago on Step 2
Should not really matter, except that the + side will oxidize (assuming it can), so you can choose between aluminum oxide, copper oxide, iron oxide, etc. Copper will turn your water green, and iron will turn your water red. Avoid using stainless or galvanized, because the results will be toxic.