Rust stains can completely ruin a driveway, garage floor, or patio area. Whether from metal furniture left out in the rain, or an old steel garage shelf that was there when you moved in, rust can be hard to lift. So, what are the best options to remove those stains?
The best concrete rust removers typically are acid-free and non-toxic. Natural remedies such as vinegar and baking soda will be effective against surface stains. Tougher solutions, including both liquid and powders, will be required for deeper-set stains.
This article will look at the causes of rust and how to prevent rust from staining your concrete floors. We will also discuss the most common rust removers on the market and look at the top 8 options for rust removal from concrete.
1. Heinz Cleaning Vinegar and Lemon Juice
Using natural products is safer, especially in enclosed spaces. For superficial stains, the strength of vinegar and lemon juice should be enough to clear rust away. The acidic qualities found in vinegar are mild enough to be used within the home but strong enough to break down any light rust spots. Additionally, lemon juice has acidic qualities that should be enough to remove more stubborn rust spots when mixed with vinegar.
Sprinkle coarse salt on the affected area and mix the two components in equal parts. Saturate the area and leave for 10-20 minutes before brushing with a hard-bristled brush.
At less than $20, this option is excellent for larger surface stains, as it is the most cost-effective and the safest to use, even indoors.
2. Arm & Hammer Baking Soda Paste
Baking soda can be used to clean everything from bathrooms to ovens and be used on less stubborn rust stains. Using a one to one ratio with generic laundry detergent, the baking soda will cause the rust molecules to become water-soluble, allowing them to be brushed away.
Make a paste with the baking soda and laundry detergent, and cover the stain thoroughly with the mixture. Allow to sit for at least an hour before brushing vigorously with a hard-bristled brush.
Given the smaller size of the box and the fact that it needs to be made into a paste, this is not suitable for larger areas. Costing under $15, one package will provide less than half a gallon of paste.
3. WD-40 Specialist Rust Remover Soak
Per their website, the WD-40- specialist rust remover soak “quickly dissolves rust and restores tools, equipment, and surfaces to bare metal without chipping, scraping or scrubbing.” For lighter stains, this will work within a few hours. Deeper stains will need to be soaked overnight.
Though this is specifically designed to remove rust from metal, the non-toxic formula contains no acids and is safe to use on concrete. It claims not to require scrubbing, but a wire brush may be necessary for more robust stains. The surface will need to be cleaned of any grease or dirt before applying this rust remover.
This option works best when the affected object can be submerged into the solution. For use on concrete, layout old towels over the rusted area and saturated them with the solution. Top up as needed, though it may take longer than the instructions indicate.
Though the cost is relatively low – just over $20 for a gallon – this product works better when the object can be completely immersed. You may find that it is not as effective on a flat surface that cannot hold the solution in place.
4. ZEAVAN Rust Paint Stripper Remover Stripping Disc
Intended for use with an angle grinder, these high-strength, soft abrasive rust removal wheels are safe to use on steel, aluminum, copper, plastic, fiber products, wood, metal, glass fiber, stone, and concrete. Their honeycomb shape and soft surface will safely remove rust and paint without scratching the surface underneath.
These discs come in a five-pack and are very durable. For surface-level stains, these would be very effective, and depending on the size, one pad should be enough. However, if looking at a larger area, you may find this to be too labor-intensive. Similarly, you might need to finish the job with some chemicals for deeper stains once the tougher areas have been cleaned.
Since one pack costs under $20, it would be enough to cover a larger area. However, it will take longer and require much more work than using a solution.
5. Row NO RUST Stain Remover Rust
Specifically designed to remove rust from flooring, this acid-free rust remover will work on surface stains in just 15 minutes. Gentle enough to use on marble, this can be applied directly onto the stain.
Apply enough of the solution so that the stain is covered and leave for at least 15 minutes. Test a small corner of the stain with a cloth and leave for a further five minutes if needed. Wipe the area clean and wash with disinfectant.
As this product does not require diluting, the small bottle should be enough for superficial stains in a confined area. However, multiple bottles would be needed for larger stains, making it very expensive compared to the bigger options, such as the WD-40 remover. One bottle costs under $28.
6. Singerman Laboratories Rust Remover for Concrete
According to their product description, this rust remover is the “most effective cleaner in the marketplace for removing rust stains from concrete and natural stone.” Available in one-pound tubs, this needs to be diluted into an equal amount of water (or three tablespoons per one cup of water). Once mixed, it should be spread liberally over the rust spot.
This rust remover should begin to work within 15 minutes. However, it is not designed to be left on for more than four hours. Test a small portion before rinsing away with a hose. You may need to scrub some more stubborn stains.
Given that this product is designed for use on cement and stone, it is one of the best options available and will cover a larger area with ease. Though it has a slightly higher price of just under $40, it is one of the only options specifically created for use on concrete and can be made up in batches to fit the area required.
7. Calcium, Lime, and Rust Remover
This solution (CLR) claims to be effective and safe to use on multiple surfaces, from stainless steel, glass, and ceramic to porcelain, cement, and brick. Designed to work on harder surfaces, the lack of phosphates makes this product safe to use on household items (and even on concrete).
Dilute the liquid per the instructions on the container, and spray liberally over the stained area. Allow to work for at least 10-15 minutes before scrubbing with a hard-bristled brush and rinsing clean.
As with the WD-40 product, you may need to saturate an old towel in the solution to soak the specific area properly. Also, at less than $15 for half a gallon, it will be more expensive if you need extra.
8. Iron OUT® Outdoor Rust Stain Remover
This premixed rust stain remover requires no diluting and work without the need to scrub the stains away. It can be used with a tank sprayer, making it perfect for any rust spots on walls or uneven surfaces. Exterior stains will only need to be rinsed clean, but you may need to scrub tougher stains.
This solution is plant-safe and can be applied with a spray, brush, or cloth. It needs to be removed once the stain is lifted, or it can leave a slight residue behind.
Another great option that states its intended use for concrete is extremely economical, at just less than $10 per gallon.
A Guide to Buying Your Concrete Rust Remover
When considering rust removers for concrete, there are a few key factors to consider:
- The type of rust remover (liquid or powder)
- Does it need diluting?
- The time it takes to work
- The cost per gallon
If the stain is on a flat surface, over a larger area, using a liquid may not be the best option. With a liquid rust remover, it will be more challenging to get good coverage over the stain, where a powder (that will become a paste) will be easier to spread over the stain, and should stay in place.
All but one of the products on this list will start to work within 15-30 minutes. The shorter activation time will decrease labor time, and will reduce the risk of pets or small children coming into contact with the solution.
Finally, though many rust removers come in larger gallon containers, some are quite small. Checking the cost per gallon will give you a better idea of the cost involved should you need to buy more than one container.
The Cheapest Option
From the information given, it is clear that the “Iron OUT® Outdoor Rust Stain Remover” is the most economical, costing almost half of most of the other options. It is specifically designed for use on concrete and can be sprayed onto any surface without fear of damaging plants. At the lower price of less than $10 per gallon, this product will go further for less.
The “ZEAVAN Rust Paint Stripper Remover Stripping Discs” are a great option if you are looking to avoid using harsh chemicals. Whether looking to protect household pets or small children, this will be a more labor-intensive option (depending on the size of the stain) but will not involve the use of any chemicals.
What To Avoid
Although the “WD-40 Specialist Rust Remover Soak” has plenty of good reviews, it might not be the easiest for use on a concrete surface. This product requires the rusted area to be completely covered to be effective. This will not be easy to do on a flat surface or a wall, and you will likely find yourself using more than required.
The Most Common Causes of Rust on Concrete
For concrete, the most common cause of rust is rain. You will find rust spots at the base of metal fencing, under steel-framed garden chairs, and even under older cars that may not have been moved in a while. If you see rust inside, it will typically be in the garage and be found under tool shelves, fridge freezers, and old bikes.
These rust spots will be seen on areas of the floor where water may pool or get stuck and where metal objects might sit. For example, some garden furniture will usually have a protective layer on the outside, but it is not uncommon to see rust develop near the base of the legs.
As the chairs are moved, cracks can form, and moisture can seep in, causing the iron to oxidize and rust to form. In bad weather, this area will also be exposed to the rain and will be in closer contact with the rain for more extended periods.
Tips for Avoiding Rust on Concrete
Rust is not something that can always be avoided, but there are ways to protect your furniture, cars, and fridges, preventing rust stains from transferring onto your concrete floors.
- Keep metal objects covered. From the garden furniture to cars that don’t get used too often, purchasing covers will help keep them dry and prevent rust from forming.
- Park cars in the garage. Keeping your vehicles inside will protect them from the elements.
- Bring garden furniture in for the winter. Rather than leaving the metal table and chairs outside during the cold and wet winter months, bring them into the garage or storage space.
- Use paste wax on susceptible areas. This will seal and protect sites that typically see the most water damages, such as the base of a shelving unit.
- Keep the garage dry. From bringing in a wet car to moving around with wet feet, water can build up in a garage, and the moisture will seep into metal objects over time.
- Place a barrier between metal objects and the concrete. This could include outdoor rugs or waterproof mats under furniture and shelving to prevent rust stains from staining the cement.
- Apply a concrete sealant. A suitable sealant will protect your concrete against everything from oil stains and tire marks to water damage and rust stains.
Removing rust stains from concrete will be relatively easy if the stain is new or superficial. It can be cleaned away with natural products like vinegar and baking soda or acid-free products made for use on cement.
You may find you need something more abrasive for tougher stains or that you need to repeat the process more than once. When applying the solution, be sure to saturate the area and scrub clean before it can completely dry.