Why Silver Tarnishes and How to Care for It

Silver tarnishes from reduced sulphur gases in the air and traces left by skin — the dark film is silver sulphide. It is thin: measured in ordinary air, about 0.5 nanometre after a day and 6 nanometres after a month. That is surface, not metal. Sterling is 92.5% silver, and the alloy underneath is untouched — a patina, not a fault.

Silver tarnishes from sulphur, not from air as such: the dark film is silver sulphide, and it keeps thickening slowly — it does not seal itself off, it only slows down.

Tarnish is a surface reaction, not damage to the alloy — a patina, not a defect.

STRUGA works in 925 silver without rhodium plating or lacquer — Living Silver: edges lighten from touch, recesses go to graphite.

Oxidised silver is different: the surface is darkened on purpose in the workshop, and aggressive cleaning strips that tone.

To clean uncoated 925 silver, a soft dry cloth over the raised edges is enough; leave the recesses alone.

Do not rhodium-plate or lacquer the piece: a film stops the metal from lightening and darkening.

• Why silver tarnishes
• How to clean silver — the safe order
• Baking soda, toothpaste, foil — what works
• What not to do
• By object — chains, rings, earrings, bracelets
• Living Silver and oxidised silver
• Storage
• If your silver came from STRUGA
• Selective brightening and the bench
• Four objects and their care
• Frequently asked questions

Why silver tarnishes

Silver does not rust — it has nothing to rust with. Rust belongs to iron; silver reacts to sulphur. The dark film is silver sulphide, and it grows from reduced sulphur gases in the air together with traces left by the skin. Two gases do that work, not one. Susan Bradley, reporting the British Museum air monitoring, put it plainly: «carbonyl sulfide was present in greater concentration than hydrogen sulfide at all of the locations monitored» — and both sit in the air at parts per billion, which is enough.

The film is thin, and it does not stop. Silver held in ordinary laboratory air, with hydrogen sulphide and sulphur dioxide below 0.2 parts per billion, builds a measurable layer on this schedule (Journal of Applied Physics, vol. 40, 1969):

Time in the air	Tarnish layer
1 hour	about 0.1 nanometre
1 day	0.3 to 0.6 nanometre
1 week	1.5 to 3 nanometres
1 month	6 nanometres or more

Growth slows as the layer thickens, but the common line that tarnish seals itself off and stops is not what the instruments show. In practice that changes nothing alarming: the reaction stays on the surface, and the alloy beneath — 92.5% silver, 7.5% copper and other metals in sterling — is not consumed.

The pace differs from person to person and place to place. Humidity is the strongest lever: between roughly 30% and 80% relative humidity the reaction accelerates sharply, and a dry drawer slows it. Perfume, sweat and household chemicals push it further. The same piece tarnishes in weeks on one hand and holds a light tone for months on another. It is about the chemistry of the skin and the environment, not the quality of the silver.

Living Silver and oxidised silver

At STRUGA the darkening is not an accident but part of the design. The 925 silver is not rhodium-plated and not lacquered: this is Living Silver. The edges a hand touches lighten over time from friction; the recesses go to graphite. Light and dark settle into a pattern of their own — different on every piece.

Oxidised silver is a separate story: here the surface was darkened in advance, on purpose. It is not "aged" metal but a choice of tone made in the workshop. Such a piece arrives already dark and tarnishes more slowly from there than a light one.

The difference is worth holding in mind before the first cleaning. Light uncoated silver can be brought back lighter. An oxidised surface will come off under aggressive cleaning — together with the very dark tone it was made for.

How to clean silver, and whether to

First the question of whether, then the how. If the dark tone suits you, leave it: with Living Silver the darkening is designed in. You clean only when you want the metal lighter.

The most honest method is a soft dry cloth. A few passes over the raised edges return their shine, and the contrast with the light edges grows sharper. The recesses stay untouched: the surface pattern lives there, and it is what gives the form its depth.

What not to do: do not send a piece for rhodium plating and do not coat it with lacquer. A thin film stops the metal from breathing — the silver will no longer lighten or darken, that is, no longer live. Aggressive pastes and "magic" solutions strip a layer of metal; on an oxidised piece that is a direct way to erase the dark tone. If the silver has darkened more than you want, a cloth and patience are enough.

Which silver darkens differently

Behind the "silver care" query, STRUGA has two different surfaces — each with its own material node and its own live collections:

• Uncoated silver: 925 silver and Living Silver — the STRUGA base. Lightens on the edges, darkens in the recesses; care is a soft cloth, when you want it lighter.
• Dark from the start: oxidised silver — the surface is darkened in advance; cleaning is rarely needed, aggressive cleaning strips the tone.
• Live collection: Blackened Silver — forms that arrive already dark.

One rule holds for all of it: dark silver needs no "rescue". You make it lighter by hand only if you wish; it stays dark by design.

How to clean silver — the safe order

Start with the gentlest thing that could work and stop as soon as it does. Every step further removes more than it should.

1. Dry cloth. A soft microfibre cloth over the raised surfaces. Most of what looks like tarnish is skin oil, and it comes off dry.
2. Warm water and mild soap. A soft brush for the recesses, then rinse and dry completely. Water left in a joint is what starts the next darkening.
3. The foil method. Line a bowl with aluminium foil, add hot water and a spoon of baking soda, rest the piece on the foil for a minute. This one is non-destructive: the dark layer reverses rather than being scraped away — the aluminium takes the sulphur, and the silver stays where it is.
4. A silver cloth, sparingly. Impregnated cloths work by fine abrasion. On a bright polished piece they are fine. On anything with worked relief they flatten the drawing.

Museum practice stops earlier than household advice does. Where conservators need an abrasive at all, they start with precipitated calcium carbonate — chalk — in a water slurry, and escalate only if it fails: gamma alumina at 0.05 microns, then alpha alumina at 0.3 microns for stubborn tarnish. Each step up the ladder takes more silver with it, and none of it comes back.

Baking soda, toothpaste, foil — what actually works

The household methods are the most searched and the least explained. They are not equal.

Soda with foil — yes

In hot water on aluminium foil, baking soda is part of an electrochemical reaction, not a scrub. The sulphide gives up its sulphur to the aluminium and the silver returns. Nothing is removed from the piece.

Soda as a paste — no

The same powder rubbed on dry is an abrasive. It works, visibly and quickly, and what it takes off is metal. On a mirror finish it leaves a haze of fine scratches; on relief it lightens exactly the depths that give the object its shape.

Toothpaste — no

Toothpaste is built to abrade. It is harsher than a silver cloth and less predictable, because the grit differs by brand.

Commercial dips — only for bright silver, briefly

Dips work by chemistry, not by abrasion: the active ingredient is usually acidified thiourea, which dissolves silver sulphide outright — about a minute is enough in conservation practice. That is why a dip clears heavy tarnish in seconds, and why it strips a deliberately darkened surface just as fast. It cannot tell a chosen surface from an unwanted one.

What not to do

• Do not dip an oxidised piece. The dark surface is the design. Seconds undo it.
• Do not use an ultrasonic bath on set stones. Vibration loosens settings and can fracture included stones.
• Do not scrub relief. The contrast between bright edges and dark recesses is what makes the form readable.
• Do not lacquer or rhodium-plate to "protect" it. A film stops the metal from lightening with wear, and when it eventually chips, the piece darkens unevenly underneath.
• Do not store silver damp. Moisture with traces of sulphur in the air is what feeds tarnish fastest.

By object — chains, rings, earrings, bracelets

Where an object is worn decides both how it darkens and how it should be cleaned.

Object	How it darkens	How to clean
Chains and necklaces	Links rub each other: outer faces stay bright, inner faces and the clasp go dark	Warm water and soap with a soft brush; lay flat to dry, never coil damp
Rings	Fastest of all — a hand meets everything; the inside of the band brightens first	Dry cloth daily is enough; soap and water when a stone is not set
Earrings and ear cuffs	Slowest — an ear is a quiet place; the post darkens before the front does	Wipe the post dry after wear; that is most of the care they need
Bracelets	Second fastest; a wrist meets tables, sleeves, keyboards	Same as chains, plus check the clasp — that is where wear shows first

Rings get the longest routine, because they take the most contact: the daily, weekly and deep passes are set out in the separate guide on how to clean silver rings. Bracelets follow the chain rule above, ear cuffs the post rule.

Storage — how silver waits between wears

Most tarnish happens while nobody is wearing the piece. Air with traces of sulphur reaches it, and there is no friction to lighten the edges back.

• Dry and closed. A pouch or a box, away from bathroom humidity.
• Separately. Pieces stored loose together scratch each other — silver is soft.
• With an absorber. A silica sachet, or a piece of chalk, takes the moisture that would otherwise feed the reaction.
• Not in rubber bands or newspaper. Both carry sulphur compounds and darken silver faster than open air.

Worn silver tarnishes more slowly than stored silver. The simplest care is use.

If your silver came from STRUGA

STRUGA works in 925 without rhodium and without lacquer — Living Silver. The metal answers to air and skin by design: edges lighten where a hand touches them, recesses go to graphite, and after a year the piece reads sharper than it did new.

So the care is mostly restraint. A dry cloth over the raised surfaces, water and soap when something needs it, and the depths left alone.

Patina can be reset. On polished silver a proper silver-cleaning liquid takes it back to bright. On a matte finish the reset is abrasive — scotch-brite or fine sandpaper — which removes a thin top layer and sets a new matte at the same time. That is a decision, not maintenance: it starts the object's life over.

Oxidised pieces are a separate case. Their darkness was set at the bench, and a dip removes it in seconds. Clean them with soap and water only.

Selective brightening, and when a bench is needed

Brightness can be returned to chosen places rather than to the whole object. A silver polishing cloth on the contact points of a ring — the raised edges a hand already lightens — sharpens the contrast against the recesses instead of flattening it. Rub only where you want light, and stop there. High-relief forms such as the Thorn Ring show it best: the points brighten with wear while the depths hold their dark.

Some work belongs to a bench rather than a cloth. A jeweller checks settings and clasps, straightens what has bent, and re-darkens an oxidised surface worn back to bright — the one operation no home method reproduces, because that tone was put there with chemistry, not with time. Once a year is enough for a piece worn daily, and less for anything that mostly waits in a box.

Four STRUGA objects, and what each one needs

The four kinds of object in the table above have names in the catalogue. The weights are real, taken from stock; all four are 925 silver without plating, so all four darken and all four come back.

• Brutalism V.3 Ring — 9.6 to 24 grams depending on size. The deepest relief in the catalogue and the fastest to change: a dry cloth over the facets is the whole routine, and the cuts are left alone on purpose.
• Thorn Links Chain — 11 to 18 grams. Links rub each other, so the faces stay light while the joints collect graphite. Soap, a soft brush, then flat to dry — a chain coiled damp darkens from the inside.
• Thorn Bracelet — 5 to 5.4 grams. A wrist meets tables and sleeves all day. Clean it like a chain and check the clasp: that is where wear shows before anywhere else.
• Brutalism Ear Cuff V.3 (L) — 3.8 grams. An ear is a quiet place, so this one darkens evenly and holds its patina longest. Wipe the contact edge dry after wear and the care is done.

Two families are represented here and each has its own shelf: the sharp relief of THORN and the heavy planes of BRUTALISM. Both belong to the CODEX world — the everyday architectural language of the brand. Forms outside the stock are made through Custom Order, in the same unplated 925.