How to clean bronze at home quickly and effectively

The question of how to clean bronze at home quickly and effectively has not lost its relevance for many decades. Bronze products look stylish and are ideal for interiors in a classic or vintage style. However, under the influence of external factors, bronze darkens, becomes covered with a green coating and loses its presentable appearance. You can correct the situation yourself using acids, household chemicals and folk remedies.

Bronze is distinguished by its dark golden color and glossy shine, but negative external factors lead to darkening of the metal and the appearance of patina. Affordable home remedies or household chemicals will help restore beauty and radiance.

The article presents the most effective and affordable cleaning methods that will return purity and shine to bronze products.

Why does plaque appear?

A freshly cast or processed bronze product is characterized by a dark yellow color. Over time, its surface begins to fade and darken, reaching a black color. Plaque occurs due to the interaction of the metal surface with air or liquid.

The air contains active substances such as oxygen, hydrogen sulfide, carbon dioxide, water vapor, and other liquids in a vapor state. The molecules of these substances react with molecules of copper and tin, forming oxides and salts. The oxide layer, consisting of copper oxide, is called black or noble patina. This surface film protects the bulk of the metal from oxidation and corrosion. Usually they don’t fight black patina, believing that darkened objects look more ancient, noble and elegant.

Plaque on bronze

There is also another type of patina - a green coating. It is also called "wild". Such stains and deposits appear due to the effect of water vapor molecules on the metal. Plaque does not cover the object with a protective layer, but destroys it, penetrating deeper and deeper into the metal layer. The surface is subject to erosion, the emerging depressions grow and turn into depressions. To prevent damage to the item, it must be cleaned using one of the many known methods at home or in a workshop.

What should not be cleaned

The main condition for cleaning copper: do not use objects that can scratch or damage its surface. Not recommended:

• Use abrasives with large grains.
• Use citric acid frequently as it can damage the surface.
• Use hard materials.

You need to take care of brass regularly: only in this case will the item retain its aesthetic appearance and delight you with its shine.

Plaque on bronze and means to combat it

Over thousands of years of using bronze objects and parts, people have tried many ways to clean bronze. Both compositions of mineral origin, plant origin and even food products were used. Of the dozens of methods, not all are suitable for use at home.

How to clean bronze using affordable means

For this you may find it useful:

• lemon juice;
• baking soda (chemical name: sodium bicarbonate);
• plain flour;
• vinegar 9% (not to be confused with vinegar essence);
• ammonia (10% aqueous solution, purchased at a pharmacy);
• aqueous solution of oxalic acid;
• finely ground chicory;
• aqueous solution of sulfuric acid;
• school chalk;
• wood sawdust.

To work you will need:

• cotton rags;
• cloth;
• wipes for drying the surface;
• stainless steel container for mixing and heating the components of the cleaning composition.

Many compounds used to clean bronze objects are chemically active and can seriously damage the skin or mucous membranes. Therefore, when working it is necessary to use personal protective equipment:

• gloves;
• apron;
• glasses or clear face shield;
• Tight clothing, shoes and hats to prevent contact of active substances with the skin or mucous membranes.

Removing plaque from bronze at home

After cleaning an item using any method, you should rinse it with water to remove any remaining composition and be sure to dry it thoroughly. Wet bronze objects become coated several times faster than dry ones.

Important! It is impossible to clean plaque on bronze once and for all. The treatment will have to be repeated periodically.

Cleaning with Natural Remedies

Since ancient times, people have used improvised means to clean bronze objects from oxidation. Many of these methods are still easy to use today to clean bronze at home.

Chicory powder

Powdered chicory used in cooking can successfully remove patina. It is used like this:

• A tablespoon of chicory is diluted in warm water. Stir until the consistency of thick sour cream.
• Apply the paste to the product and wipe off stains with a soft brush. For small items or relief details, it is convenient to use an old toothbrush. The pressure should be soft.
• Rinse the item with plenty of water and dry thoroughly with napkins.

Cinnamon powder

Peas

The popular legume plant perfectly cleans the bronze surface of dust, soot and other foreign contaminants. The sequence of actions is as follows:

• The products that are going to be cleaned are placed in a container with several spoons of peas.
• The container is filled with water so as to completely cover the bronze objects.
• The water is brought to a boil and simmered over low heat for 2-3 hours.
• The items are transferred to another container and cooled.
• The surface is wiped with a soft brush or cloth to remove any remaining dirt.

The surface should be thoroughly dried.

What is brass and where is it used?

Brass is an alloy of copper and zinc. Tin, manganese, lead, nickel, and aluminum can be added to it. The composition affects the color and properties.

Zinc, the main component of brass, was only discovered in the 16th century. At the same time, people knew about it before our era. For example, in Rome they made alloys of copper with zinc ore and created dishes and jewelry.

Then production began in Central Asia, from there the accessories came to Rus', where their unique shine and high quality were also appreciated. After zinc was discovered in 1746, brass appeared in the form familiar to modern times.

The standard formula is the proportion of copper and zinc 1 to 2. Now zinc can be added much less, no more than 30 percent. For technical alloys the percentage increases to 50%. The more zinc there is in a product, the lower its price.

Such alloys are considered one of the most common; they are called eternal metals because they hardly wear out. Two-component types, where zinc is 20 percent, are used for automobile spare parts, coils, and heating equipment. The 40% composition is suitable for stamped products and accessories. Multi-component brasses have a very wide range of applications. They are used to make aircraft, pipes, watches, springs, and ships.

Tombac, which contains up to 10 percent zinc, is used to create artistic accessories and decals. Cages, fittings and bearings are made from cast brass to provide rust resistance. Automatic alloy is used for fasteners.

Resistance to magnetic attraction makes it possible to make compasses, and high heat capacity makes it possible to make samovars. Objects for the church are made from brass, such as the frame of an icon. The cost of the alloy is quite low, and prestigious items such as the famous Zippo lighters are made from it.

It is also successfully used in jewelry. Yellow, golden and green types are used. If it contains 15% zinc and 5% aluminum, the item looks very similar to gold. A good specialist is able to create a product from such an alloy that will be difficult to distinguish from a precious metal.

Cleaning with household chemicals

If natural remedies do not help, you can use more powerful compounds from the arsenal of household chemicals. The most harmless among them is a specially designed raster for cleaning copper, brass and bronze “Trialon-B”. It is used by numismatists to clean valuable coins. The concentrated product is diluted with water 1:10, the product is lowered into the solution and its surface is carefully monitored. As soon as the plaque has dissolved, the object is immediately removed with tweezers, washed with water and thoroughly wiped dry.

Using Chemicals to Clean Bronze

Bronze cleaning can also be done with the following substances:

• Ammonia, or ammonia. To clean a bronze item, you need to lower it into a container with a solution and after a couple of minutes remove it, rinse and dry it.
• Acetone.
• Oxalic acid.
• Soda Ash. Used for large products for which it is not possible to find a container of sufficient size. Moisten a brush or cloth with an aqueous solution (1:20) and wipe the areas covered with plaque.

After wiping, rinse the surface with plenty of water and dry it thoroughly.

Acetone

To clean bronze items, you can use a strong organic solvent - acetone. A cotton pad is soaked in solvent and rubbed into contaminated areas. When discs become dirty, they should be replaced with clean ones; the more often the better.

Acetone

When working with acetone, it is necessary to have exhaust ventilation - inhaling large amounts of vapor can lead to loss of consciousness and poisoning. Or the treatment must be carried out outdoors. After wiping, the product must be rinsed and dried.

Oxalic acid

A potent chemical is used in advanced cases when it is not possible to clean with other means. You can buy oxalic acid at a pharmacy or chemical store. To clean plaque, you need to:

• Prepare the solution. For 5 liters of cold water, take 100 ml of acid.
• Immerse the items to be cleaned in the solution. They should be completely covered with liquid.
• After the liquid darkens, the products should be removed from the solution.
• Next, you need to rinse them with plenty of water and dry thoroughly.

To enhance the effect of the solution, aluminum sulfate is sometimes added to the acid.

Attention! Concentrated oxalic acid is hazardous to health. The use of personal protective equipment is mandatory. The room should be well ventilated.

Paste GOI

The polishing paste, developed at the State Optical Institute and named after him, is intended for polishing metal and non-metallic surfaces. It contains fine-grained abrasive substances and, if handled carelessly, can destroy the smallest details of the relief. Therefore, it is recommended to use it for objects of simple design that do not have artistic value and fine relief. The paste is prepared independently, the finest corundum powder is mixed with wax or paraffin. Or it can be purchased ready-made in stores.

Sulfuric acid and potassium

Sulfuric acid is an even more potent reagent than oxalic acid. When working with it, special care must be taken. It is used to clean deeply patinated items. The operation sequence is as follows:

• Prepare a glass container of sufficient volume. Metal utensils will not work - sulfuric acid will dissolve them.
• Pour a liter of cold water into it.
• Add 20 grams of potassium dichromate and stir.
• Slowly pour in 20 ml of concentrated sulfuric acid over a glass rod.

Important! You can't pour water into acid! This will cause hazardous chemicals to splash.

• Place the items to be cleaned in an acidic solution.
• Prepare a second container with ammonia.
• After the patina is corroded by acid, carefully remove the bronze objects with tweezers or hooks and soak them in ammonia.
• Rinse with plenty of water and dry thoroughly with paper towels or a soft-lint cotton cloth.

There is no such thing as excessive caution when working with sulfuric acid.

Ammonia

Candelabra, candlesticks, large figurines, and antique watch cases cannot be cleaned with ammonia. However, it will handle small items, coins and medals well. Cleaning proceeds as follows:

• Ammonia is poured into a deep container.
• Place the items to be cleaned in the container so that they are completely covered with liquid.
• Leave for a few minutes to half an hour, observing the state of the patina.
• After achieving the desired effect, the items are removed, washed with plenty of water and dried thoroughly.

To consolidate the cleaning effect, it is recommended to treat the surface with alcohol and paraffin.

When working with ammonia, you should use personal protective equipment, including a respirator. The room must be well ventilated or equipped with exhaust ventilation.

Cleaning gold plated items

It is better to entrust the cleaning of bronze items with gilding to professionals who are well versed in the rules of mixing chemical reagents. If you decide to independently restore the appearance of a product using chemical reagents, then be very careful.

The cleaning itself is carried out in two stages.

1. First prepare an alkaline solution. Mix 1 tbsp. l. caustic potassium or sodium with 1 tbsp. l. water. Use the prepared product to carefully remove stains, dirt and dust.
2. Then prepare a solution of 30 ml of water, 8 ml of nitric acid and 1 g of aluminum sulfate. Using a soft brush, apply the product to the item and dry it in the sun or near a heat source.

Another means for cleaning gilded bronze is prepared from 50 g of nitric acid, 40 g of alum and 0.5 tbsp. water. Apply the product with a brush to the item and leave for 10-15 minutes. After the specified time, polish thoroughly.

Cleaning with Food Products

Many common foods can play an unexpected role. They can also remove patina from bronze items.

Soda and lemon juice

Baking soda and the juice of one or two lemons can be used for other purposes.

• Equal volume fractions of baking soda and lemon juice are mixed to the consistency of thick sour cream.
• The resulting composition is applied to the areas captured by the patina, rubbing with smooth movements.
• Leave the mixture on the surface for up to half an hour.
• Wash off the composition with plenty of water and dry thoroughly with napkins.

Cleaning Bronze with Lime

In this way, it is possible not only to remove the patina, but also to return the product to a mirror shine.

Vinegar, flour and salt

Another “kitchen” remedy can be a composition mixed from wheat flour, table salt and 9% vinegar.

• Wash and dry bronze items.
• In a small container, mix salt and flour in equal volumes.
• Add vinegar so that after thorough mixing you get a mixture with a consistency reminiscent of thick sour cream.
• Apply the mixture to the patina-covered areas and, pressing lightly, rub over them.
• Repeat application and rubbing 2-3 times.
• Leave for half an hour to an hour, depending on the depth of the patina.
• Rinse the composition off the surface, rinse it with plenty of water and dry thoroughly with paper or cotton napkins.

Apple vinegar

If the process of patina formation has not gone too far, then this method can also return the surface to a mirror shine.

Wood sawdust

A slightly exotic, but very effective way to clean bronze items, used by our distant ancestors:

• Pour approximately half the volume of sawdust into a glass container with vinegar essence (60%).
• Let the sawdust swell
• Pour the mixture into a cloth and polish problem areas with it.
• As the mixture becomes dirty, change it by adding it again.
• After cleaning, rinse the items with plenty of water and wipe dry.

When handling vinegar essence, the same precautions should be taken as with sulfuric acid. Vinegar is weaker, but not much.

Electrolysis method

Those who paid due attention to physics lessons are familiar with this concept from school. Its usefulness when processing coins will be ensured if the following two important rules are observed:

• compliance with safety regulations;
• testing the method on inexpensive items in order to avoid damage to more valuable products.

It is worth paying special attention to the second point of the operating principles: the fact is that sometimes, due to a minor mistake, serious, irreparable damage is caused to a coin or other valuable item.

Old coins are restored to their purity and shine through the use of a small power supply (6-12 Volts). As such, a universal charger can be used. Another alternative: an old mobile phone charger.

The following are attached to the power supply or its alternative:

• two alligator clips;
• some small metal object (not copper or brass is recommended);
• deep dishes made of glass or ceramics.

A saline solution is also used, prepared in compliance with the following proportions: 1 tablespoon of salt per 1 liter of water.

The process is simple, you just need to follow all the steps exactly. One clip - with a minus sign - is attached to the specimen, while the opposite one - with a plus sign - is attached to a metal object.

Then the coin and the metal product are lowered into a pre-prepared container where the saline solution is located, while the power supply is plugged into the outlet.

The result makes itself known quite quickly: the process of dissolving oxides and dirt leads to rapid clouding of the solution. The “bathing” period is short, after which the specimen is washed with hot water and dried.

A little care and precision in following all steps will allow you to achieve the desired results.

Prevention of oxidation

Once things have been cleaned of patina, it’s too early to calm down. Air and water vapor continue to attack the metal and the patina may return.

To prevent the reappearance of plaque, preventive measures should be taken. To do this, the surface, after removing the patina, is treated with substances such as:

• wax;
• paraffins.

They are applied with a soft sponge or cloth, then the surface is rubbed and polished. A thin protective film is created on it, preventing contact of metal molecules with air oxygen and water vapor.

Wiping a bronze object after treatment

The most affordable means of prevention can be an inexpensive toothpaste that does not contain fragrances or dyes. It can be applied conveniently with an old toothbrush, especially if the product has a complex multi-level texture. The product, evenly coated with toothpaste, is thoroughly rubbed with a soft cloth until shiny.

For greater safety, it is better to store bronze objects separately from each other, wrapping each one in a piece of suede or velor. When storing valuables, it makes sense to place a bag of silica gel next to them, which absorbs excess moisture from the air.

All of these precautions are good for coins and rarely used jewelry. Actively used bronze parts, for example, trim and parts of the rigging of a yacht, cannot be protected in this way. They will have to be processed regularly.

It is better to take particularly valuable items to a workshop for cleaning. It's not that expensive, but it guarantees the safety of things. Experienced craftsmen will not make mistakes in the dosage of chemicals or the exposure time.

Rust removal

From time to time, bronze products become covered with a coating of corrosion. You can also defeat him with a slightly unusual reagent, which is ordinary yellow peas. There are two popular ways to use peas:

• The peas are boiled to a thick porridge. The resulting composition is used to cover the corrosion areas and leave until the mixture dries. Next, the dried pea paste is removed, the product is washed with plenty of water and thoroughly dried with napkins.
• The method is suitable for small things that fit in a pan. Several handfuls of peas are poured with water and brought to a boil. After boiling, the things that need to be cleaned are dipped into the broth and boiled over low heat for two to three hours. Next, the items are removed from the broth, washed with plenty of water and dried thoroughly. Pea particles are removed from uneven terrain with a soft brush.

Rust on bronze