What are the best ways to remove rust from metal?

Saturday, January 28, 2023

The results that can be achieved from restoring items covered in rust can be quite incredible. From old spanners, knives, to scissors, screws, padlocks and even gardening shears, there's many a device that could do with a spruce up. 


There are many handy tricks you can use to remove rust. 


Some are organic and others are heavy-duty methods such as using strong hydrochloric acid.


Let's explore what ways really work and cover a little bit of the science around rust removal and why rust occurs.


Rust is a form of corrosion that occurs when iron or steel is exposed to oxygen and moisture. The oxygen reacts with the iron to form iron oxide, which is commonly known as rust. The process can be accelerated by the presence of salt, acids, or other chemicals. 

That's why things corrode quicker than you may expect when you live in a coastal environment - there's plenty of moisture with salt content blowing in from the ocean!

removing rust with acid

There are several simple home-based remedies that can be used to remove rust from items like scissors or gardening tools. 

Some tired and true methods include:
  • White vinegar and baking soda: Mix equal parts white vinegar and baking soda to create a paste. Apply the paste to the rust and let it sit for several hours or overnight. Scrub the rust with a stiff brush and rinse with water.
  • Lemon juice and salt: Mix equal parts lemon juice and salt to create a paste. Apply the paste to the rust and let it sit for several hours or overnight. Scrub the rust with a stiff brush and rinse with water.
  • Coca-Cola: Soak the rusted item in a fizzy glass of Coca-Cola for several hours or overnight. Scrub the rust with a stiff brush and rinse with water.
  • Potatoes: Cut a potato in half and dip the cut end in baking soda. Rub the potato on the rust and let it sit for several hours or overnight. Scrub the rust with a stiff brush and rinse with water. Potatoes contain oxalic acid, which is a mild acid and that's what does the job here. 
  • Steel wool: Use steel wool to scrub the rust. Be careful not to scratch the surface of the metal too much. Steel wool is excellent for scrubbing the bottom of cook pots!
  • Sandpaper, wire brush, or sandblaster: If the rust is not too severe, you can use sandpaper or wire brush to remove it. Sandblasting is a powerful way to remove rust from metal surfaces but it takes proper set up and room outside to do this. 
Note that some of these methods may not work for heavy rust and severe corrosion, and in those cases the use of chemical compounds such as strong acid may be required.

Those tips about potatoes and Coke for rust removal seem crazy eh? 

Like you drink Coke, yet it can dissolve rust? 

Is it true Coca-Cola removes rust from dirty nails?


Coca-Cola contains phosphoric acid, which can dissolve rust. The acid in the Coca-Cola reacts with the rust to dissolve it, making it easier to scrub off.

It is true that Coca-Cola can remove rust from a nail if left overnight. The acid in the Coca-Cola reacts with the rust, breaking down the bonds that hold the rust to the nail. Soaking the nail in Coca-Cola for an extended period of time allows the acid to penetrate the rust and start dissolving it. However, it's important to note that this method is not as effective as using a rust remover, and it may take several soaks to fully remove the rust, and it might not be as effective as other options mentioned above.

It's also important to note that using Coca-Cola to remove rust from metal objects is not a widely accepted practice, as Coca-Cola is not a rust remover, and it may contain sugar, caramel, and other ingredients that can stain the metal. 

If you want to remove rust from metal objects, it's best to use a rust remover specifically designed for that purpose.

rust nails and screws remover

How does a white vinegar and baking soda combination paste remove rust from metal?

The white vinegar and baking soda paste works to remove rust from metal by a process called chelation (chelation is a process of removing metal ions from solution by binding them to a chemical compound).

White vinegar, also known as acetic acid, is a mild acid that can dissolve and loosen rust. The acidity in the vinegar reacts with the rust, breaking down the rust into a form that can be easily removed.

Baking soda (sodium bicarbonate) is a mild abrasive that can help scrub away rust. Baking soda also acts as a pH buffer, neutralizing the acidity of the vinegar.

When mixed together, the acetic acid in the vinegar and the baking soda react to form carbonic acid, which can help to dissolve the rust. Additionally, the abrasive properties of the baking soda can help to scrub away the rust particles.

The chemical reaction that occurs between vinegar and baking soda is an acid-base reaction. The acetic acid in the vinegar reacts with the baking soda (sodium bicarbonate) to form carbonic acid (H2CO3), water (H2O) and sodium acetate (C2H3NaO2).

H3C-COOH + NaHCO3 -> H2CO3 + NaC2H3O2 + H2O

The carbonic acid that is formed in this reaction is weaker than the acetic acid and it helps to dissolve the rust. Additionally, the abrasive properties of the baking soda can help to scrub away the rust particles.

The paste works by breaking down the rust and making it easier to remove. The paste should be applied to the rusted area, left for several hours or overnight, then scrubbed off with a stiff brush. Repeat the process if necessary. Rinse the item thoroughly with water.

How does lemon juice and salt work to remove acid from a bath or shower?


As a home remedy, lemon juice and salt can be used together to help remove rust and mineral buildup from a bath or shower due to the acidic and abrasive properties of the ingredients.

Lemon juice is acidic and contains citric acid, which can react with and dissolve rust and mineral buildup. The acidity of lemon juice can help to break down and remove mineral buildup, such as hard water stains, soap scum, and rust.

So this tip is ideal for bathroom and shower use. 

Salt, on the other hand, is abrasive and can help to scrub away the buildup. When mixed with lemon juice, salt can act as a scouring agent, helping to remove the buildup by scrubbing.

To use lemon juice and salt to clean a bath or shower, you can make a paste by mixing equal parts lemon juice and salt together. Then, apply the paste to the affected areas and scrub with a scrub brush. Leave the paste on for a few minutes to allow the acid to work, then rinse the area with water. 

In our personal experience, this is not 100 per cent effective and it can be hard to remove the last bit of rust stain. I once had rust rings form in the bath because of a cheap can of shaving cream - this trick does work but you have to use a bit of elbow crease to get the job done.

rust removal with HCL

Can you use hydrochloric acid to remove rust from metal?


Yes, hydrochloric acid (HCl) can be used to remove rust from metal. 

Hydrochloric acid is a strong mineral acid that can effectively remove rust by breaking down the iron oxide (rust) into iron chloride, which can then be easily washed away.

The process of using hydrochloric acid to remove rust from metal involves immersing the rusted metal object in a solution of hydrochloric acid and water. The concentration of acid in the solution can vary depending on the severity of the rust and the type of metal. A common concentration for removing rust is 10-20% hydrochloric acid.

It's important to note that using hydrochloric acid can be dangerous and should be done with proper safety precautions and protective gear. Additionally, hydrochloric acid can be corrosive to certain types of metal, so it's important to test a small area before treating the entire object.

After the rust is removed, the metal should be thoroughly rinsed with water to neutralize any remaining acid and remove any traces of the iron chloride. 

The metal should then be dried and oiled to prevent future rust.

It's also important to note that hydrochloric acid can cause skin burns, eye damage, respiratory problems, and other health hazards if not handled properly. If you are not familiar with handling chemicals, it is not recommended to use hydrochloric acid to remove rust from metal.

Wise advice to follow we reckon. 

Here's the actual science of how hydrochloric acid works is magical on rust:

The science of using hydrochloric acid (HCl) to remove rust from metal involves a chemical reaction that converts the iron oxide (rust) into iron chloride, which can then be easily washed away.

Rust is a form of iron oxide, which is a compound made up of oxygen and iron. When rust forms on metal, it creates a layer of iron oxide on the surface of the metal. Hydrochloric acid reacts with the iron oxide by breaking down the compound into its individual elements. The acid reacts with the oxygen in the rust, creating water and leaving behind the iron.

The reaction can be represented by the following equation: Fe2O3 + 6HCl → 2FeCl3 + 3H2O

In this equation, Fe2O3 represents the rust (iron oxide), 6HCl represents the hydrochloric acid, 2FeCl3 represents the iron chloride, and 3H2O represents the water produced in the reaction.

The iron chloride that is formed in this reaction is water-soluble, which means it can be easily washed away with water. Once the rust has been converted to iron chloride, it can be removed by rinsing the metal with water.

It's important to note that hydrochloric acid can react differently with different types of metal, some metals may react with acid and form toxic fumes or other dangerous by-products. Therefore, it's important to test a small area before treating the entire object and to use proper safety precautions when handling hydrochloric acid.

What steps should be taken after using acid to remove rust from metal?


After using acid to remove rust from metal, there are some steps that you could considering doing to ensure that you have long-term success - i.e. stop or delay the rust from coming back.

Neutralize the acid: After the rust has been removed, the metal should be thoroughly rinsed with water to neutralize any remaining acid. The best way to neutralize hydrochloric acid is by using a baking soda solution. Adding baking soda to the water will neutralize the acid and create a solution of sodium chloride (table salt) and water.

Thoroughly rinse with water: Rinse the metal with clean water to remove any traces of the acid, iron chloride, and baking soda solution. If possible, use a pressure washer or a hose to thoroughly remove all traces of the acid from the surface of the metal.

Dry the metal: Once the metal has been rinsed, dry it thoroughly. If the metal is not dried completely, it may rust again.

Oil the metal: Once the metal is completely dry, apply a rust inhibitor or oil to the surface of the metal to prevent rust from forming in the future.

Properly dispose of the used acid solution: The used acid solution should not be poured down the drain or left in open containers, as it can be dangerous to the environment and to the people who come into contact with it. The used solution should be placed in a sealed container and disposed of properly.

Consider personal protection: It is important to wear gloves, goggles and a mask when working with acid and to wash your hands and face thoroughly after handling acid.

Check the item: Before using the metal object, inspect it to make sure it is safe to use. If the metal is thin or weak, it may not be safe to use after the rust has been removed.

removing rust from tool bits screws

What is a rust inhibitor and how is it correctly applied?



A rust inhibitor is a substance that is applied to metal surfaces in order to prevent the formation of rust. Rust inhibitors work by creating a barrier on the metal surface that prevents oxygen and moisture from coming into contact with the metal. This barrier can be either a physical barrier, like a coating of oil or wax, or a chemical barrier.

There are different types of rust inhibitors available, each with its own unique properties and application methods. 

Some rust inhibitors are applied as a liquid or spray (think CRC related products), while others are applied as a powder or paste. 

Some rust inhibitors are formulated specifically for use on outdoor metal surfaces, while others are designed for use on indoor metal surfaces.

When applying a rust inhibitor, it is important to follow the manufacturer's instructions and to use the product as directed. The general steps for applying a rust inhibitor are as follows:

  • Clean the metal surface: Before applying a rust inhibitor, the metal surface should be thoroughly cleaned to remove any dirt, grime, or rust that may be present.
  • Apply the rust inhibitor: The rust inhibitor should be applied in a thin, even layer to the metal surface. Depending on the type of rust inhibitor, it may be applied with a brush, roller, or sprayer.
  • Allow the rust inhibitor to dry: After the rust inhibitor has been applied, it should be allowed to dry completely. The drying time will vary depending on the type of rust inhibitor and the humidity and temperature of the environment.
  • Inspect the metal surface: Once the rust inhibitor has dried, the metal surface should be inspected to ensure that it is fully covered and that there are no areas that have been missed.
  • Reapply as needed: Depending on the type of rust inhibitor and the environment in which the metal is located, it may be necessary to reapply the rust inhibitor periodically in order to maintain its rust-preventing properties.

What are some popular commercial rust removal products that home owners can use?

There are many commercial rust removal products available for homeowners to use, some popular options include:

Naval Jelly: This is a gel-like rust remover that is applied to the surface of the metal using a brush. It's a very popular all round rust remover. 

Evapo-Rust: This is a liquid rust remover that can be used to remove rust from metal surfaces without damaging the underlying metal. It can be used on a wide range of metal surfaces, including iron, steel, aluminum, and more.

CLR Calcium, Lime & Rust Remover: This is a liquid rust remover that is designed to remove calcium, lime, and rust deposits from metal surfaces. It can be used to remove rust from a wide range of metal surfaces, including iron, steel, and aluminium.

Metal Rescue Rust Remover Bath: This rust remover is a liquid solution that can be used to remove rust from metal surfaces by immersing the metal in the solution. It can be used to remove rust from a wide range of metal surfaces, including iron, steel, and aluminum.

Zep Heavy-Duty Citrus Degreaser: This is a liquid rust remover that can be used to remove rust from metal surfaces as well as grease and oil. 

It is important to follow the manufacturer's instructions when using these or any rust remover products, and to use them in a well-ventilated area, wearing gloves and goggles for safety. Some rust remover products may be toxic and harmful if ingested or inhaled, so it is important to be cautious and store them properly. 

Also, some rust removers may not be compatible with certain types of metal or coatings, so it is important to test the product on a small, inconspicuous area first before applying it to the entire surface.

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