Why Do Cutlery & Silverware Tarnish? (10 Facts + Help Tips)

Silver, aluminum, and stainless steel cutlery can tarnish or discolor, but what causes the issue?

Cleaning and protecting them against tarnish are possible.

why silverware turns black and cutlery tarnish in dishwashers

Why Silver, Stainless Steel, or Aluminum Flatware

Did you get a set of silver cutlery as a wedding present, or perhaps you collect antique silver and have an impressive tableware collection of knives, forks, spoons, teaspoons, ladles, jam spoons, and other specialist cutlery items from across the ages?

Silver or silver-plated flatware (the technical name for your knife, forks, and spoons is flatware or silverware regardless of material) are beautiful to use and lend a degree of polish to your table setting.

But is it practical to use silver cutlery when everyone knows that silver is prone to ugly tarnish?

Or perhaps your flatware is stainless steel or aluminum; will it stay bright and clean for life?

1. Flatware Materials

You get flatware in various materials and combinations, including:

  • Pure silver.
  • Sterling silver.
  • Plated silver.
  • Stainless steel.
  • Aluminum.
  • Wooden handles.
  • Bone handles.
  • Acrylic handles.
  • Decorative plated (gold, copper, or colors) cutlery.

Cutlery with silver will tarnish, and stainless steel, despite the name, can tarnish and discolor with use.

In the nineteenth century, the novelty value of aluminum meant it was suitable for cutlery to display the host’s wealth.

Your cutlery is unlikely to be aluminum unless you’ve bought custom-made or vintage.

Decorative vintage flatware from Russia is often aluminum, but most people opt for stainless steel for practical, affordable knives, forks, and spoons.

2. Why Does Flatware Turn Black?

Your knives, forks, spoons, and other cutlery react with the environment, and some processes result in corrosion.

Gases in the Atmosphere

Silver reacts with sulfur to form silver sulfide, and copper forms copper sulfide – both these compounds are black.

Pure silver is slow to react unless in direct contact with hydrogen sulfur or other sulfur-containing gases.

Copper is faster, and plated silver tarnishes more rapidly than pure silver.

Stainless steel reacts with oxygen and will oxidize in time.

Aluminum also oxidizes, but aluminum oxide is transparent and forms a protective layer that does not disfigure the flatware unless it is dirty.

Food Stains

The food you eat contains chemical compounds, and some react with the metal in your cutlery.

If you use a silver spoon to eat your boiled egg, the spoon turns black on contact with the yolk because the yolk contains hydrogen sulfide in sufficient quantities to trigger a reaction.

The acids in acidic foods also react with the metals in your flatware, causing staining and tarnish.

Your cutlery reacts with the food on your plate and subtly alters the taste.

Leaving food in contact with your silverware can promote tarnish and other stains.


Water is rarely pure; typically, water in contact with your knives, forks, and spoons contains other water-soluble compounds that may react with the metal in your flatware to form tarnish.

Plus, when water evaporates, it leaves deposits of minerals behind that can stick to your cutlery and attract dirt.

The oxygen in the water will result in rust through the formation of iron oxide if left in contact with stainless steel.

Storing your cutlery in a damp environment or not drying after washing will result in water staining and increased tarnish.

Mixed Metals

Storing silver, steel, and aluminum cutlery in the same drawer can cause reactions between the different types of metal.

Some cleaning solutions use aluminum foil and cleaning agents to clean silverware with this reaction, but accidental contact can have undesirable results.

Overenthusiastic Polishing

Although tarnish is unsightly, the process protects the underlying metal.

If you keep polishing off the tarnish on your silver spoons, you keep exposing the new metal to the air.

Plus, you keep removing a layer of silver – in plated silver, you can lose the entire silver plating to excess polishing.

Museum silver is rarely cleaned and kept in a protective atmosphere where possible.

Flatware in daily use doesn’t have this protection, but you can keep your knives shiny without excess polishing.

Contact with Skin

The best silver service waiters and museum staff wear white cotton gloves when handling silverware.

Your skin contains oils and other chemicals that react with steel, silver, and other metals.

Professional embroiderers wash their hands and regularly change their needles because of skin oils, sweat, and metal reactions.

3. Why Does Cutlery Turn Black in the Dishwasher?

The dishwasher is efficient at cleaning dishes with minimal effort from you, but it can wipe the patterns of expensive plates and leave your flatware less than its sparkling best.

Inside the dishwasher contributing causes to turning your tableware black and stained include:

Food Stains

Food contains chemicals that can react with metal forks, knives, and spoons.

Your cutlery is likely to remain in contact with food for longer as most people wait for a full dishwasher load.

You can remove food by rinsing the flatware before putting it in the dishwasher, but it may be quicker to wash and dry your cutlery instead.


Inside the dishwasher, your silverware may remain wet for longer and has exposure to hot, humid conditions during the drying cycle.

Heat and humidity can increase the amount of tarnish.

The most frequent complaint about cutlery in dishwashers is that they come out watermarked as evaporating water droplets leave mineral deposits behind.

Contact with Other Metals

Putting your silver spoons in the same basket as your stainless-steel knives allows both metals to react together during the washing cycle.

Cutlery separation improves the cleanliness and prevents tarnish from mixed metal contact.


Dishwasher detergent is harsher and more abrasive than dish soap.

Plus, your dishwasher powder may contain bleach or citric acid.

Dry powder in direct contact with your silverware is corrosive.

Your dishwasher isn’t perfect at rinsing all the detergent from your knives and forks, and in stainless steel, this inadequate rinsing may result in detergent bloom, coloring your cutlery blue.

4. Tarnish on Different Metals

How tarnish develops on your utensils depends on the metal involved.


Tarnish on silver is the equivalent of rust on steel, although the chemical reactions involve different gases.

Silver reacts to gases containing sulfur; the combination of silver and sulfur forms Silver Sulfide or, in the case of plated silverware, a mixture of silver sulfide and copper sulfide.

With their different color from silver, these compounds are tarnish.

Pure silver tarnishes slower than plated silverware, but in both cases, tarnish is not attractive on your knives, forks, and spoons. Your guest is unlikely to want to eat with tarnished silverware.

The color of tarnish varies depending on the depth of the tarnish coating.

The silver sulfide is black, but a light passing through a thin layer can produce optical effects showing as yellow, reddish-brown, and blue.

The tarnish color indicates how thick a layer of tarnish is present.

Stainless Steel

Tarnish on stainless steel results from a reaction with oxygen or sulfur, and the discoloration is a combination of a layer of mixed oxides and sulfides.

The tarnish causes discoloration, and previously shiny spoons seem permanently dirty.


Aluminum reacts with oxygen in the air to form an Aluminum oxide, but this clear compound provides a protective layer on the surface of the aluminum.

Typically, you won’t notice the tarnish unless you observe dirt sticking to it—aluminum cutlery classes as tarnish-free.

Aluminum cutlery in the dishwasher may discolor due to the chemicals from detergent or food and reactions with other metals.

5. Tips to Protect Cutlery in the Dishwasher

Before cleaning your cutlery in the dishwasher, you must ensure that the cutlery is dishwasher safe.

Any cutlery with ornamental handles of bone, plastic, or wood is best washed by hand unless specifically certified as suitable.

Don’t Mix Your Metals

If you have mixed cutlery made with different metals, ensure plenty of separation or segregate and wash in separate loads.

Metals react together, and the best way to avoid this process is with physical separation.

Rinse Before Washing

It may seem odd to clean your knives and forks before putting them in the dishwasher, but it makes sense to remove food stains to stop the chemicals in the food from reacting with the cutlery.

The dishwasher will give a hygienic clean but washing off food debris and drying the cutlery before the dishwasher cycle will help minimize tarnish.

Dry and Polish

As soon as your dishwasher cycle stops, remove your silverware and finish drying it with a linen or cotton cloth.

Eliminating water and using the slight abrasion of the fabric will polish your cutlery, so it shines and is tarnish-free.

Avoid Harsh Detergent

Avoid dishwasher detergent containing sulfides, citric acid, or bleach if you want to keep your flatware shiny and bright.

It will help diminish tarnish if you balance the competing demands for cleaning glass and ceramics with the gentler approach necessary for your best silverware.

6. Cleaning Tarnished Silverware

If your silverware has a thick black coat of old tarnish, you need a specialist polishing cloth for best results.

If the tarnish is a pale yellow, washing in water with soft dish soap and then drying and polishing with a linen or cotton cloth will remove the tarnish layer.

Silver tarnishes in the air and contact with water.

Careful storage in a dry box with cloth wrapping the silver knives, forks, and spoons will slow the rate of tarnish.

Typically, the best approach to silver cutlery is to polish it before use.

If in daily use, a linen glass cloth will remove tarnish with minimal loss of silver. If your silver is for occasional celebrations, don’t clean the tarnish until you are ready to use the cutlery.

The tarnish layer protects the cutlery from further silver loss.

7. Cleaning Tarnished Stainless Steel

An effective way to clean stainless steel flatware is to use contact with aluminum foil.

Use aluminum foil to line a large skillet capable of accommodating all your cutlery or work in batches with fresh foil each time.

Spread your tarnished stainless-steel knives, forks, and spoons on a single layer across the foil.

Mix a teaspoon of salt and one of baking powder in a jug of warm water and pour into the skillet. Add more water until the pan is seventy-five percent full and the cutlery is covered.

Bring to the boil and boil for five minutes – leave to cool before draining and removing the cutlery.

Use a dry cotton or linen cloth to polish each knife, fork, and spoon to a gleaming finish.

8. Removing Dishwasher Rust Stains

To remove rust stains from your steel cutlery, use a clean microfiber cloth and a paste made from baking soda and a little warm water.

Use the cloth and a little of the paste to polish away any rust spots with a gentle circular action.

After you’ve finished, rinse the item and dry thoroughly.

9. Why Does Silverware Turn White?

Ornate silver knife and fork handles have places where silver polish gets trapped.

The polish can give your silverware a dull white appearance.

After polishing your intricate silverware, you can rinse in warm water and scrub the polish out of the crevices.

Dry with a clean cloth and buff to a high shine.

10. Should You Hand-Wash Cutlery?

Handwashing and careful drying are effective ways of cleaning and maintaining your best knives, forks, spoons, and serving utensils.

They will last longer because the dishwasher is abrasive, but it depends on how regularly you need to use your utensils.

You might want to compromise with dishwasher-friendly inexpensive cutlery for daily use and washing in the dishwasher.

Then you can spend a little extra time pampering your antique silver on those special occasions when you set your table for a celebration.


Silver cutlery will tarnish regardless of how carefully you maintain and store it.

The tarnish is a natural process, and you can still enjoy your precious silver by making time to polish your silverware.

You can wash all your cutlery in the dishwasher, but you may need to spend more time rinsing and stacking.

You know whether it is easier for you to use the dishwasher or routinely handwash your cutlery.

If your flatware gets tarnished, you don’t need to worry because tarnish is straightforward to remove.

If excess use and cleaning, remove the silver layer from your silver-plated cutlery; it is relatively inexpensive to have it replated.

Whether you favor handwashing or machine washing, don’t let the idea of tarnish spoil your enjoyment of your quality flatware.