Why Medals Develop Tarnish and What It Means

A medal can look perfectly sound when placed in a drawer, then appear dull, spotted or darkened months later. For veterans, families and collectors, that change can be unsettling, particularly where an award carries service history or has been prepared for ceremonial wear. Understanding why medals develop tarnish helps distinguish a normal surface change from damage that needs careful attention.

Tarnish is not simply dirt. It is a chemical reaction between a medal’s surface and elements in its surroundings, most commonly oxygen, moisture and sulphur-containing pollutants. The precise appearance depends on the metal, its finish, how it has been handled and where it has been stored. A little ageing may be entirely expected. Aggressive corrosion, staining or flaking is different, and calls for a more cautious approach.

Why medals develop tarnish

Many British military and civilian medals are made from, plated with, or contain alloys of silver, bronze, copper, nickel, gilt or cupronickel. Each reacts differently over time. Silver commonly develops a grey, brown, purple or black film when it meets airborne sulphur compounds. Bronze and copper alloys may darken to brown or develop green deposits. Gilt surfaces can lose their brightness where plating is thin, worn or affected by unsuitable cleaning.

The reaction is often most visible in recessed lettering, around the rim, beneath a suspension bar and in the detail of the obverse or reverse. These areas hold moisture and airborne particles more readily than raised surfaces. Tarnish can therefore make fine die-struck detail appear less crisp, even where the medal itself remains structurally sound.

Humidity is a major factor. A medal kept in a damp loft, garage, cellar or external store is exposed to repeated changes in temperature and moisture. Condensation can form in frames, cases and drawers without being obvious. Even a room that feels dry can become problematic if medals are stored against an outside wall or close to a radiator, where temperatures fluctuate.

Air pollution also plays a part. Domestic heating, traffic pollution, cooking vapours and some household materials release compounds that can affect metal over time. Older display cases, cardboard boxes, foam inserts, rubber bands and certain adhesives may give off sulphur or acidic vapours. A medal stored carefully but in the wrong material can tarnish faster than one kept in open air under stable conditions.

Handling leaves more than fingerprints

Skin oils, perspiration, hand cream and cleaning residues transfer easily to polished metal. Fingerprints may not show immediately, but can develop into uneven marks as salts and oils react with the surface. This is especially noticeable on bright silver finishes and on medals that have recently been professionally cleaned.

Handling is sometimes unavoidable, particularly when preparing a mounted group for a parade, remembrance event or family display. The sensible practice is to hold medals by their ribbons or edges, with clean dry hands. Soft cotton or nitrile gloves are useful when examining collectible or historic pieces, provided they are clean and do not catch on ribbon fabric or fittings.

Tarnish, patina and corrosion are not the same

A uniform soft darkening on an older bronze medal may be described as patina. It can be historically appropriate and, for collectors, may contribute to the medal’s character. Removing it indiscriminately can reduce appeal and erase the natural evidence of age. The same judgement applies to original named medals, campaign groups and awards with scarce or sensitive finishes.

Tarnish usually sits on the surface and may be reversible when treated correctly. Corrosion is more serious. Green, powdery or waxy deposits on copper-based metals can indicate active corrosion. Pitting, lifting plating, rough patches, deep black staining, or metal that appears to be crumbling should not be polished in an attempt to restore shine. Abrasion can expose fresh metal and make the problem worse.

The right standard depends on the medal’s purpose. A current replacement or replica medal intended for wear may reasonably be kept bright and parade-ready. An original family group may be best preserved with minimal intervention. There is no single finish that suits every award.

Materials that make medals tarnish more quickly

Silver is particularly prone to tarnish, but it is not the only metal that needs thought. Sterling silver contains copper, which can add to surface change. Silver-plated medals may show uneven colour if the plating is worn. Bronze and copper alloys react strongly with moisture, while nickel and cupronickel can become dull or develop localised spotting.

Mixed-metal medal groups present another consideration. A collection may include silver campaign medals, bronze commemoratives, gilt insignia and modern cupro-nickel awards. If they are stored together in direct contact, surface abrasion and transferred residues can occur. Medals should be separated by inert, non-abrasive material rather than wrapped tightly in ordinary paper, tissue or plastic film.

Ribbons deserve equal care. Damp can encourage mould, fade colours and weaken fibres. Metal polish, water and chemical dips can wick into the ribbon from the suspension and leave permanent marks. For mounted medal sets, improper cleaning can also affect backing materials, stitching, pins, brooches and clasps.

How to reduce tarnish without over-cleaning

The most effective preservation method is stable, clean storage. Choose a dry indoor location away from direct sunlight, radiators, kitchens and bathrooms. A well-made medal case, frame or drawer with suitable inert lining gives physical protection as well as a more controlled environment.

Avoid sealing medals in conditions where moisture may already be present. If an award has been worn in rain, exposed to damp air or brought in from a cold vehicle, allow it to dry naturally at room temperature before returning it to a case. Do not place it on a radiator or use direct heat, which may harm ribbons, adhesives and plating.

For medals worn regularly, a light wipe with a clean, soft, dry microfibre cloth after handling can remove fresh fingerprints. This is not the same as polishing. The aim is to remove surface oils without rubbing away metal or protective finishes. Do not use kitchen roll, abrasive cloths, toothpaste, household metal cleaners or ultrasonic devices. Their apparent short-term results can conceal scratches, lost detail and damaged plating.

A stay-bright coating may be appropriate for certain replacement medals, replica sets or awards intended for regular ceremonial wear. It creates a protective barrier that can reduce routine tarnishing and simplify maintenance. However, it is not automatically suitable for every original medal. Coatings can alter appearance and, if poorly applied or applied over existing residue, may create problems later. The medal’s age, metal, condition and intended use should guide the decision.

Cleaning historic and mounted medals

An original medal should never be cleaned simply because it is old. Before any work is undertaken, assess whether the discolouration is stable, whether a named edge or fine relief needs protecting, and whether the medal is part of a mounted group. Historic awards can have collector value that is affected by polishing, replating or alteration.

Professional cleaning is often the safer choice where there is active corrosion, stubborn staining, a delicate gilt or silvered finish, or a complete court-mounted group. A specialist can determine whether cleaning is advisable, protect ribbons and fittings, and retain the appropriate character of the award. Empire Medals can also advise on cleaning, mounting and stay-bright finishing where a medal is being prepared for presentation or wear.

For a medal group that is framed, inspect the display periodically. Look for condensation beneath the glazing, ribbon fading, insect activity, loose fittings or a sudden change in metal colour. Early attention is gentler and usually more effective than attempting to reverse years of deterioration.

When tarnish tells part of the story

A bright medal is not always a better medal. Service medals have been worn, handled, polished for parade and stored through decades of family life. Their surfaces can reflect that history. The aim is not to make every award look new, but to keep it stable, legible and respectfully presented.

If a medal’s finish changes quickly, develops green deposits, or leaves residue on the case lining, remove it from the affected environment and seek specialist advice before cleaning. Careful storage and restrained handling will do more for a medal’s long-term condition than any aggressive polish ever can.