Why silver tarnishes, and how to outsmart it

Here is the most reassuring fact in jewellery: tarnish is what real silver does. The metal is reacting with the air, not failing.

What's actually happening

Silver reacts with sulfur compounds in the air, mainly hydrogen sulfide, to form a very thin film of silver sulfide. At first it looks like a faint warm glow, then golden-brown, and eventually black. It sits on the surface, which is why it can be removed. Silver underneath is untouched.

What speeds it up

Two things: sulfur, and moisture. Humidity speeds the reaction dramatically, and a surprising number of everyday things give off sulfur:

• Wool and felt: including the felt lining of many old jewellery boxes.
• Rubber: rubber bands, latex gloves, some carpet underlay.
• Food: eggs, onions, mayonnaise and salty foods.
• Air: cooking fumes, pollution, and bathroom steam.
• You: the salt and oils on skin, plus perfume, hairspray and lotion.

How museums store silver

Conservators keep silver in sealed polyethylene bags, sometimes with activated charcoal nearby (not touching) to absorb sulfur, and aim for relative humidity below 50%. You don't need a museum. You need the same three ideas at home:

1. Seal it. A small zip bag with the air pressed out, or an airtight box.
2. Absorb it. An anti-tarnish strip or a sachet of silica gel inside, replaced every few months.
3. Keep it dry. Never in the bathroom. A drawer in a bedroom is ideal.

The easiest prevention of all

Wear it. Gentle friction from wearing, plus a soft wipe afterwards, keeps silver bright. The pieces that tarnish worst are the ones left alone for years in a box. We know that story better than most.

Caught it early?

A light golden film comes off with a soft cloth. For stone-set or plated pieces (like most of ours), use warm water with a drop of mild soap and a soft brush, then dry completely. Never use silver dip on stones or coloured finishes. Here's why.