Some cleanup chores are tougher than others—and among the most challenging are oil stains on the driveway, paint spills on the garage floor, and mildew marking the foundation. That’s because most stains on concrete are created by tough materials like petroleum products, paint, and living organisms such as mold, mildew, and algae. What’s more, concrete is porous and tends to soak up these substances, so once they penetrate deep into the surface they’re especially difficult to dislodge. Choosing the right concrete cleaning method is key—as is using the right cleaner for the job.
The best concrete cleaners, both liquid and dry applications, attack stains deep below the surface. However, the variety of materials that cause concrete stains requires matching the cleaner to the type of stain. If you’re dealing with dirty concrete, one of these products should be able to help.
- BEST OVERALL: Zep Neutral pH Floor Cleaner Concentrate ZUNEUT128
- BEST BANG FOR THE BUCK: Sunnyside 64216 TSP All Purpose Cleaner
- BEST ECO-FRIENDLY: ACT Concrete Cleaner
- BEST FOR PRESSURE WASHING: Simple Green Oxy Solve Total Pressure Washer Cleaner
- BEST WATERLESS: CAF Outdoor Cleaning EXIMO Waterless Concrete Cleaner
- BEST DEGREASER: Oil Eater Cleaner Degreaser
- BEST FOR MOLD AND MILDEW: RMR-86 Instant Mold and Mildew Stain Remover Spray
What to Consider When Choosing the Best Concrete Cleaner
With many concrete cleaners to choose from, you may wish to understand how they work to remove different types of stains. Just ahead, find out how stains are classified, which cleaners work on the different kinds of stains, and other useful tips that can help you choose the best concrete cleaner for your project.
Biological stains are caused by living organisms such as mold, moss, and algae. They often appear as green streaks, film, or cushiony growth over a broad area on concrete surfaces that stay damp. This can be a recurring problem in humid areas, so it’s helpful to have a fast-acting, long-lasting solution. Home remedies like scrubbing with bleach or white vinegar are commonly recommended, but commercial cleaners do the job faster, more thoroughly, and can help prevent regrowth.
Spills and leaks of hydrocarbons (petroleum products like motor oil), cleaners, paint, and solvents also cause unsightly concrete stains. These products penetrate the porous surface of the concrete causing discoloration, and in some cases chemical reactions that may physically degrade the concrete surface. Be sure to choose a cleaner that is recommended for use on the particular spilled product: Enzyme cleaners can neutralize many volatile compounds, eliminating their negative environmental impact, and absorbent cleaners pull the spilled product out of the concrete.
In choosing an appropriate concrete cleaner, be aware that different cleaners act in different ways to banish stains, and they also react differently to the concrete surface. Cleaners may use pH neutral, alkaline, or acidic formulas to chemically lift stains. Concrete is made with lime, which is alkaline, so the surface must be neutralized after using acid cleaner. Enzyme and bacteria-based cleaners use biochemical reactions to digest or degrade chemical pollutants into inert substances.
- pH neutral cleaners are often used to clean sealed concrete surfaces indoors without embedded dirt. They can also be used on unsealed concrete indoors or out, if the concrete needs only a mild cleaning.
- Alkaline concrete cleaner is a powerful degreaser designed to remove burned oil, tar, soot, grease, and other petroleum-based stains.
- Acid concrete cleaner is made with hydrochloric acid or phosphoric acid that reacts with the concrete surface. It is used to remove efflorescence, hard water stains, and other scaly mineral salt buildup.
- Enzyme cleaners come in different formulations that attack, break down, and in some cases digest hydrocarbon, starch, or protein-based stains. These cleaners use genetically modified bacteria that feed on grease and oil.
Concentration and Form
Concrete cleaners come in either liquid or dry applications. Most liquid concrete cleaners are for biological or mineral stain removal. They are typically chemical-based cleaners, although some may be enzyme based. Ready-to-use formulations are fast and convenient, while concentrates, which must be diluted with water before use, are often more economical.
Dry concrete cleaners are made to separate hydrocarbon stains from the surface of the concrete and absorb liquids. Bacterial cleaners are applied dry. The microbes activate when they come into contact with hydrocarbons and then slowly consume the remnants of the stain until it is gone.
With such a variety of cleaning products, cleaning methods vary as well. Regardless of the product, be sure to read and follow all safety, application, cleanup, and disposal instructions.
Many of the concentrated liquid products are well suited for use as a pretreatment before pressure washing. You can use these products without a pressure washer, but serious scrubbing with a stiff bristle brush would be required for thorough cleaning, followed by a thorough rinse. After using an acid-based cleaner, it is necessary to neutralize the concrete surface with a wash solution of ½ cup of baking soda mixed with 1 quart of water, followed by a thorough rinse with clean water.
Dry-product cleaning methods vary as well. Absorbent and enzyme cleaners typically get the job done within a few hours; afterward, they are swept up and reapplied if needed. Bacteria-based cleaners are meant to be left in place indefinitely, as it can take several weeks for the microbes to fully colonize the area.
Cleaning time could take as little as a minute or as long as several weeks. Biological stains like algae and mold are relatively easy to kill and clean, whereas cleaning deep-set hydrocarbon stains with an enzyme or bacterial cleaner can take a long time. The major difference in working time, as mentioned previously, is due to the way the product works.
Chemical reactions such as the separation of grease from concrete by an alkaline cleaner occur more quickly than bacterial digestion of petroleum. But the trade-off is that the fast-acting cleaner leaves petroleum pollutants intact, while the bacterial treatment converts the pollutant into water and carbon dioxide.
The environmental impact of concrete cleaning products varies based on the nature of the stain or spill being cleaned—and the product itself. Care should always be taken to remove and properly dispose of toxins, rather than dispersing them into the environment.
Pressure washing spreads debris from the concrete surface into the surrounding environment, so it is effective and safe for use on biological stains accompanied by eco-friendly cleaners. Potential environmental pollutants like oil or gas should ideally be remediated by enzyme or bacteria-based cleaners whenever possible.
While concrete cleaners are safe when stored and used properly, they pose inherent risks for skin contact, ingestion, inhalation, and other accidental exposure. Keep these products stored out of the reach of children and pets. Never store them in unmarked containers. Always heed the manufacturer’s instructions for safe use, including the use of personal protective equipment, safe storage, and first aid in case of emergency.
Our Top Picks
The following concrete cleaners were selected according to the criteria outlined above. They are considered among the most effective cleaners to combat the toughest stains, including oil stains on the driveway, paint on the garage floor, and mildew on the foundation.
Zep Neutral pH Floor Cleaner Concentrate is a great choice for sealed concrete floors as well as marble, granite, vinyl, and stone (do not use on wood floors). The neutral pH formula helps maintain the floor’s polish without stripping the protective coat. It cleans and restores shine without rinsing.
This concentrated formula makes up to 128 gallons of cleaning solution, saving on storage space. Zep recommends using a microfiber mop with this product instead of a traditional string mop for improved maneuverability and more efficient cleaning without leaving a residue.
The active ingredient in Sunnyside TSP All Purpose Cleaner is trisodium phosphate, a powerful alkaline cleaner, degreaser, and paint remover that is safe for concrete surfaces. It’s about one-third the cost of many other cleaners, yet effective at removing dirt, grease, mildew, and soap scum from a wide range of soiled surfaces. It’s also a solid choice to prep concrete surfaces for paint.
Mix between ¼ and ½ cup of this powdered concentrate with a gallon of hot water for a powerful cleaning solution. TSP is best used for indoor cleaning of basement and garage areas, as the high phosphate content is problematic if it leaks into streams and other water sources. Use caution and protection when mixing and using, as TSP is highly alkaline and capable of causing severe skin irritation or burns.
ACT Concrete Cleaner effectively releases oil, grease, antifreeze, gum, animal waste, and mold stains from concrete, pavers, wood, soil, plastic, and other surfaces without scrubbing. It uses the same effective processes employed by the oil and gas industry and commercial warehouses to break down and bioremediate petroleum hydrocarbons as well as proteins (it does not remove paint). Stain materials are converted to water and carbon dioxide.
Simply apply the dry cleaner to the stained surface, work it into the stain with a broom or brush, and let it sit; you should see full results in three to four weeks. This product is environmentally friendly and safe for use around people, animals, and plants.
Use Simple Green Oxy Solve Total Pressure Washer Cleaner before pressure washing as a pretreatment to weaken the bond of stains to concrete, or use it in the pressure washer’s cleaning solution reservoir for one-step cleaning. This cleaner employs the power of peroxide to deep clean dirt, grime, mold, mildew, moss, and algae stains.
The biodegradable formula meets the criteria of the U.S. Environmental Protection Agency’s Safer Choice Program, and it’s safe for use around pets, landscape plants, and wildlife. It is suitable for concrete and other materials including wood, composite, vinyl, metal, fabric, plastic, wicker, stone, brick, and asphalt. Use it on driveways, foundations, siding, and more.
EXIMO Waterless Concrete Cleaner uses microbes to break down hydrocarbon chains in oil to lift away concrete stains caused by gas, diesel, oil, grease, petroleum-based materials, and more. It is a powerful, environmentally safe, natural, waterless cleaner that is highly effective against stains but completely safe for surrounding landscape plants and grass as well as people and pets. It is suitable for wet or dry parking areas, sidewalks, concrete patios and stairs, pavers, and other similar surfaces.
Apply by working the product into the stain with a broom, and leave it on the surface; no need to sweep it up or wash it off. Apply weekly for four weeks for complete stain removal. Living microbes in the cleaner follow stains and spills deep below the surface, consuming petroleum through tiny crevices in the concrete and even into the subsoil below.
Oil Eater Cleaner Degreaser is formulated to safely dissolve grease and oil on most surfaces. It is nonacidic, noncorrosive, nonhazardous, contains no abrasives or petroleum solvents, and is USDA approved for nonfood surfaces. The water-based and biodegradable product is concentrated, so follow the dilution chart on the label to use it as a light, medium, or heavy-duty degreaser.
In addition to banishing grease and oil stains on concrete, it can be used on household floors, carpet, tub and tile, grills, decks, stoves, boat hulls, tires, siding, asphalt, and many other surfaces.
RMR-86 Instant Mold and Mildew Stain Remover is a fast-acting spray that utilizes deep penetrating surfactants with a unique blend of pure sodium hypochlorite to remove stubborn stains. Surfactants loosen the bond between the soil and the concrete’s surface, while the powerful bleaching properties of sodium hypochlorite kill mold and mildew on contact.
This potent cleaner comes as a ready-to-use, sprayable solution and is powerful enough to dissolve mold and mildew stains in seconds without scrubbing. It is safe for use on decks, wood, vinyl siding, drywall, concrete floors, brick walls, kitchen and bathroom tiles, bathtubs, and other areas where mold and mildew grow.
FAQs About Concrete Cleaners
If you still want more information about concrete cleaners, read on for answers to several common questions about these products.
Q. Are concrete cleaners harmful to pets?
Always keep children and pets away from the area while using concrete cleaner, and store the products out of their reach. Once cleaned, the area is immediately safe for normal use.
Q. What can I use to clean a concrete driveway?
Remove oil stains and other hydrocarbons with a bioremediation cleaner. For tough algae or moss growth, spot clean with a contractor-grade hypochlorite-based cleaner. Use an acid cleaner to deep clean and remove efflorescence. For general cleaning of a dirty driveway, a pressure washing cleaner will do the trick.
Q. What do you spray on concrete before pressure washing?
The process of pressure washing is made easier and more efficient if the surface is pretreated with a concrete cleaner. Apply the cleaner at low pressure and allow it to stand for three to five minutes before pressure washing.
Q. Will rust come off concrete?
Rust stains on concrete require a specialized acidic cleaner to remove.