How to Clean Antique Brass and Copper Safely

Brass candlesticks, copper pots and old door hardware can look dull and dark after years in storage. This guide is for owners and sellers who want to clean these pieces without harming them. You will learn how to decide whether to clean at all, the gentlest methods to try first, and when to stop and get professional help.

First, decide whether to clean

Not every piece should be polished. The dark, mellow surface on old brass and copper, called patina, is something many collectors value. Polishing it away cannot be undone, and on some items it lowers value.

• Leave alone or ask a professional about bronze sculptures and art objects. Their patina is often an intentional finish applied by the artist or foundry.
• Be cautious with pieces that may be lacquered. Many brass items were coated with a clear lacquer at the factory. Polishing through it causes blotchy spots.
• Do not polish pieces that are gilded, enameled, painted or silver-plated over brass or copper.
• Archaeological finds, rare early pieces and anything you believe is especially valuable should go to a conservator.

If you plan to sell, consider leaving the piece as found. Many buyers prefer to decide for themselves.

Confirm what the metal is

Hold a magnet to the piece. Solid brass and copper are not magnetic. If the magnet sticks, the item is likely steel or iron with a brass or copper plating, and heavy polishing can wear through the thin outer layer. Treat plated items very gently.

Start with the gentlest cleaning

1. Dust the piece with a soft brush or cloth.
2. Wash it in warm water with a few drops of mild dish soap, using a soft cloth or soft brush for crevices.
3. Rinse with clean water.
4. Dry thoroughly and right away with a soft towel, since standing water can leave spots.

For many pieces, a simple wash removes grime and old fingerprints and is all that is needed. Stop here if you like the look.

If you choose to polish

If you want a brighter surface, use a commercial polish made for brass or copper that is labeled non-abrasive or gentle. Test it first on a hidden area such as the base.

• Apply a small amount with a soft cotton cloth and rub lightly in the direction of any grain or existing polish lines.
• Work in small sections and switch to a clean part of the cloth as it darkens.
• Remove all polish residue from crevices with a soft brush, then wash, rinse and dry the piece.
• Stop when you reach the look you want. You do not have to remove every bit of darkening, especially in recesses, where it adds depth.

What to avoid

• Steel wool, scouring pads, wire brushes and power buffing wheels, which scratch the surface and remove detail.
• Harsh household chemicals and strong acids.
• Soaking pieces for long periods, especially if they have joints, solder, wood handles or attached parts.
• Dishwashers, which can discolor and damage the metal.

Home remedies made with lemon juice, vinegar, salt or similar acidic ingredients do work on tarnish, but they can etch the surface, leave a pinkish or uneven color, and cause new tarnish if any residue remains. If you use them, use them sparingly, rinse very thoroughly and dry completely. A gentle commercial polish is usually easier to control.

Copper cookware

Many old copper pots and pans are lined with tin on the inside. Do not polish the lining with copper cleaner. Clean the interior with soap and water only. If the lining is worn through to copper, the piece should be re-tinned by a specialist before you cook with it, or kept as a decorative item.

Green spots and corrosion

Green or blue-green deposits, often called verdigris, are a form of corrosion. Light spots on everyday items may come off with gentle washing and polish. Heavy, crusty or spreading corrosion, or corrosion on a valuable piece, is a job for a conservator, since aggressive removal can leave pits.

Keep it looking good

After cleaning, a thin coat of microcrystalline wax, applied and buffed with a soft cloth, slows tarnish and is easy to remove later. Handle cleaned pieces with clean, dry hands or cotton gloves, since skin oils leave marks.

Quick checklist

• Decide whether the patina should stay.
• Use a magnet to check for plated steel or iron.
• Wash with mild soap and water first.
• Test any polish on a hidden spot.
• Avoid abrasives, soaking and dishwashers.
• Send bronze, valuable or corroded pieces to a conservator.