How to Clean Pearls

Why pearls are the exception on this site

Almost every care page here recommends some version of the same thing: warm water, a drop of mild soap, a soft brush, a rinse, a thorough dry. That method is safe on gold, gold-filled, sterling, steel and titanium. On pearls, most of it is wrong.

A pearl is not a mineral in the way a sapphire is. It is nacre - microscopic platelets of calcium carbonate, laid down in overlapping layers and bound together by an organic protein called conchiolin. The lustre people pay for is light reflecting off and through those translucent layers. That is an organic, laminated, porous structure, and three things follow:

• Acid dissolves calcium carbonate. Vinegar, lemon juice, descalers and most “natural” cleaning remedies attack nacre directly. The reaction is not subtle and it is not reversible.
• Detergents and solvents attack the protein. Strip the conchiolin binding the platelets and the surface goes chalky, which is exactly the lustre loss you were trying to prevent.
• Nacre is soft. Around 2.5 to 4 on the Mohs scale, against 10 for diamond and 7 for quartz. Dust is largely quartz. A pearl rubbed with a gritty cloth is being sanded.

What a pearl actually is, and the difference between natural, cultured and imitation, is the subject of pearls explained. All five pearl pieces on this site are cultured freshwater pearls - genuine pearls grown in a mollusc, which behave exactly like natural ones for care purposes.

What is safe and what is not

That is an unusually long list of nevers for a material that needs so little. The whole positive instruction is: wipe them, occasionally use a damp cloth, dry them flat.

The habit that matters more than cleaning

“Pearls go on last and come off first” is the oldest piece of jewelry advice there is and it is the single most useful sentence on this page. It matters most on the one day pearls are most likely to be worn - see pearls for weddings and bridesmaid jewelry gifts, both of which run into a room full of hairspray. Perfume, hairspray, hair products, lotion, sunscreen and makeup are all either alcohol-bearing or mildly acidic, and they are the main cause of lustre loss over a lifetime - not a failure to clean, but repeated contact with cosmetics.

The corollary: pearls should be worn, not stored. Nacre contains water within its structure, and skin contact in normal humidity keeps it in reasonable condition. A strand left in a sealed box or a bank vault for twenty years can dry out and craze. That is one of very few cases in jewelry where using something is better for it than protecting it.

Knotted strands: the part people get wrong

A good pearl necklace is strung on silk with a knot between each pearl, which stops the pearls abrading each other and means a broken thread loses one pearl rather than all of them. Silk is also the reason a strand must never be soaked: wet silk stretches, and it holds whatever it absorbed inside the knots, next to the nacre, for days.

• Wipe pearl by pearl rather than running the whole strand through a damp cloth.
• Dry flat on a towel, never hanging - wet silk stretches under the weight.
• If the thread between pearls looks gray, frayed, or if the pearls have visibly spread apart, it needs restringing. That is a jeweler's job and an inexpensive one.
• Restringing is the normal maintenance schedule for a frequently worn strand - roughly every couple of years of regular wear, more often if it is worn against skin in heat.

Pearls set in metal

A pearl stud, pendant or drop is easier than a strand because there is no silk involved - but it introduces a different conflict: the metal may want a cleaning method the pearl cannot survive. A pearl on a sterling setting that has tarnished is the awkward case, because every silver tarnish remedy on how to clean silver jewelry is unsafe for the pearl next to it.

The method is to treat them as two materials. Work polish onto the metal with a cotton bud or a cloth corner, keeping it entirely off the pearl, then wipe the pearl separately with a clean damp cloth. Never dip the piece, and never use an ultrasonic - which rules out the two fastest ways to clean silver. If the setting is badly tarnished, a jeweler can do it properly and will know to mask the pearl.

One of the pearl pieces on this site uses gold-filled wires rather than plated ones, which is worth knowing for exactly this reason: gold-filled needs no tarnish treatment, so there is never a conflict between caring for the metal and caring for the pearl.

What cannot be fixed

Be straight about this, because a lot of advice is not. Lost lustre from cosmetic contact, surface pitting from acid, crazing from dryness and the chalky look of stripped nacre are all permanent. There is no polish, cream or dip that restores nacre - anything claiming to is removing a further layer of it. Professional repolishing of pearls exists and it does exactly that: takes nacre off to reach a better surface underneath, which only works if the nacre was thick to begin with.

This is why the wipe-after-wear habit is the whole of pearl care. There is no recovery step, so prevention is the entire strategy. Fortunately prevention takes ten seconds and the picks above cost less than a single pearl.

If you are buying rather than maintaining, the pieces where the metal is as durable as the pearl are ranked on best pearl jewelry under $100.