Caring for Japanese Lacquer, Iron Kettles and Bronze

The first rule: ask before you treat

Every object has its own history of repairs, finishes and wear. The notes below are general, drawn from museum and maker guidance. Any washing, polishing or treatment should be decided for the individual piece — if in doubt, ask us first.

Lacquer (urushi)

Urushi is a natural tree resin applied in thin layers, usually over wood. Museum sources name light and changes in humidity as its main enemies.

• Light: keep lacquer out of direct sun and strong artificial light; damage builds slowly and dulls the surface. The Smithsonian's National Museum of Asian Art limits display time for lacquer; at home, rotate pieces between display and rest.

• Humidity: lacquer over wood can crack or lift as the wood moves; choose a stable room away from radiators, fireplaces, vents and damp walls.

• Handling and dust: use clean hands or gloves and support from below. Dust is abrasive — lift it with a very soft brush (hake) without rubbing. No household polishes or sprays.

• Water: wiping or washing should be decided case by case; light-damaged lacquer can be harmed by water before any change is visible.

Read more about the technique in What Maki-e Is Made Of and Kodai Ujiie: Lacquer and Crackled Ceramics.

Iron kettles (tetsubin)

We cannot confirm that any particular kettle is safe for boiling water or drinking. Old or decorative kettles should be examined by a specialist before use with water or heat.

• Handle with clean, dry hands or gloves; do not lift by a loose handle (tsuru) — support the body.

• Iron rusts in damp: keep it dry and ventilated, away from kitchens and bathrooms and from direct heat.

• Dust with a soft dry brush; never scrub, scour or use metal polish.

• New orange rust or flaking? Ask before doing anything.

The Nanbu Ironware Cooperative (Morioka) advises, for kettles in regular use, not to scrub the interior, not to leave water standing and to dry it after use. These are instructions for kettles made for use, not for restoring old pieces.

Copper and bronze

Japanese copper and bronze vessels usually carry a patina, natural or deliberately applied by the maker; it is part of the work.

• Never polish. The Canadian Conservation Institute notes that the patina on Asian bronzes is highly prized and should never be polished. No polish, cleaners, vinegar or lemon.

• Gloves: fingerprints can etch copper alloys; museums recommend clean nitrile gloves (freshly washed cotton is also used).

• Environment: dry and stable; green or powdery spots may be active corrosion — ask before treating.

• Support from below, never by handles, rims or projections.

Boxes are part of the object

Many Japanese works come in a fitted wooden box tied with a flat cord (sanada-himo). Keep it: inscriptions can be part of the work's history. Carry the box from below, not by the cord. See How to Read a Japanese Tomobako.

Display and storage at a glance

	Lacquer	Iron	Bronze
Light	Limit, rotate	Not critical	Not light-sensitive like paper
Humidity	Stable	Dry	Dry, stable
Cleaning	Soft brush only	Soft dry brush	Soft dry brush; never polish
Store in a stable, dry, dark place; avoid attics, garages and basements.

Seasonal looking

Lacquer and gold maki-e are often described as most beautiful in low, warm, indirect light; the arare texture of a kettle reads best in low side light; raking light shows cast and chased detail on bronze.

Ask about a specific piece

Have a question about caring for a specific piece? Ask us through our Collector's Inquiry.