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How to Remove Rust from an Allen Wrench?


This is a close look at a rusty set of Allen wrenches on the ground.

One of the most frustrating aspects of upkeeping your tools is the seemingly endless battle against rust. Unlike a rusted screw, Allen bolt, or drill bit you can simply replace, your hand tools are worth much more. Due to their size, Allen wrenches often can be that overlooked or misplaced tool that is left outside or at the workbench.

If that happens, chances are your wrenches have started to rust or are already rusty. For those of you who may have a rusty allen wrench or four, please read on for solutions to getting the rust off your wrenches.

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How Does Rust Form on Your Allen Wrench?

It is essential to know why and how rust can form on your allen wrenches. As most allen wrench keys are either iron or stainless steel, water is their worst enemy. When moisture is left on your wrench, the oxygen and water begin to oxidize the metal; this causes corrosion that forms rust on the surface of the metal.

Because of this corrosion, it is crucial to ensure your hex wrench is wiped down and stored in a dry place to avoid this rusting process.

Rust Eventually Ruins Your Allen Wrench

This is a close look at a set of Allen wrenches tainted with rust.

Rust weakens the metal of your allen wrenches, and if left alone, it will sap the strength from the metal until the wrench breaks. Rust effectively turns strong iron or stainless steel into a flaky powder. Another damaging aspect of rust is how it can damage the wrench’s hex ends so it will not fit appropriately in an allen screw head.

If the rust forms around the ends of the allen wrench head, it can flake off and change the wrench’s size. This will make it so the hex key will not fit into the bolt head properly. To avoid this, I have compiled a list of methods for removing rust from your allen wrenches.

Method 1: Muscle the Rust Off

The most common method for removing rust from any hand tool is to scour it off using something rough like sandpaper. As rust forms on the allen wrench or hex wrench surface, sanding it off can be the easiest place to start. It is essential to clean the tool first and then use sandpaper on the dry metal.

Different grit level sandpaper can be helpful. Starting with a coarse grit initially will help get the heaviest stuff off. Near the end, it can be useful to switch to finer grit sandpaper.

Sometimes using a wire brush or steel wool helps in the rustier places, but since allen wrenches are so small, you can start with the sandpaper. With any luck, sanding the wrenches will remove most of, if not all, the rust. This is the best way to start; however, another method may be necessary if the sandpaper does not work.

Method 2: Spot Cleaning

After scouring the wrenches, you may find that most of the rust came off, but some trouble spots remained. The following methods are suitable for smaller rust spots that simply can’t be sanded or scrubbed away. Both can be managed from home with everyday household items.

Baking Soda

This is a wooden bowl with baking soda and a wooden scoop.

For the following method, you need only look into your baking supplies. Baking soda is widely used to get rid of stubborn stains in clothing and floors. It has an abrasive texture that makes it great for scrubbing.

Baking soda can also be used to remove rust from your allen wrenches. To do this, mix baking soda and water so that it forms a paste. Next, apply the paste to the rusty areas of the Allen wrench and leave it applied for several hours.

Finally, use a wire brush or steel wool to scrub off the paste. You will see that the paste dissolved the rust, and the wrench will be bright and new-looking. This process may need to be repeated depending on how much corrosion is present on the wrench.

Lemon Juice and Salt

This is a mixture of sea salt and lemon in a glass jar.

As the baking soda method, you can use salt and lemon juice to remove rusty spots on an Allen wrench. The salt and juice create a chemical reaction that eats away the rust. Simply put some salt on the rusty area, apply some lemon juice and leave it there for a couple of hours.

Later, scrub away the lemon juice and salt solution to remove the rust spots from your allen wrench. This method can be abrasive to the wrench, so it is vital not to leave it on for too long. This method also has the perk of making your tools smell fresh and clean afterward.

Method 3: A Chemical Bath

If your hex key set is so rusted that not even sanding or scrubbing helped much, it may be in need of a good soak. The following methods provide chemical soaks that will soften up or eat away the corrosion from your allen wrench. While these methods may take longer, they are the best for tools with extreme corrosion.

Vinegar and Salt

This is a close look at vinegar, salt and other eco-friendly natural cleaners.

The following method may take slightly longer, but it is another effective way to remove rust from your allen wrench. Mixing salt with white vinegar can create a solution that will soften up and dissolve rust. The ratio of salt to vinegar should be one tablespoon of salt for each cup of vinegar.

After mixing the solution, place your rusty wrench in the mixture and let it sit for at least a day, but it may take longer. Periodically check on the wrench to see if the rust is softening and will scrub off. When the rust is sufficiently soft, use a wire brush or steel wool to scrub the wrench clean of the rust.

After the soak and scrub, your wrench will shine and be ready for use. This method is also very safe. The salt and vinegar are not as abrasive as other chemicals that can be used to remove rust.


This is a glass of Coke with ice cubes on a kitchen counter.

Coke can also be used to soak your rusty hex key set to remove the rust. Douse your wrench in some fresh Coke, and the soda will eat away the rust. Like the Vinegar and Salt solution, this process does require more time to be effective.

It would be best if you tried to allow at least 24 hours while periodically checking the wrench. It is vital that when soaking a rusty allen wrench in Coke, one does not mistake it for a beverage. After sufficient time, scour the rust off with a wire brush or steel wool.

One downside to this method is that it is somewhat stickier than others.

Method 4: The Store-Bought Route

The final method for removing rust is simply going and purchasing a rust remover. Most rust removers use harsh chemicals like Oxalic Acid. What this means is, more protective equipment should be used when using these methods.

Always pay attention to the instructions on the rust remover, which should illustrate how to mix the solution and what protective wear is needed. Generally, most acidic rust removers will require some eye protection like goggles and something for your hands like rubber gloves.

It is also essential to adhere to the instructions regarding ratios for mixing and how long to leave the allen wrench in the acidic solutions.


Home Depot: How to Remove Rust from Tools

Farmer’s Almanac: Rust Remedies