Because of cars, the lawn mower, tools, motorcycles and other outdoor equipment, dirt build-up and oil and grease stains are inevitable on a concrete garage floor.
Unfortunately, you are not always able to address a mess right away, or maybe you're looking to clean oil off your concrete garage floor that's been there for who knows how long. Unless sealed, cured concrete is not a hard, dense rock - the mixture of cement, sand, and aggregate is porous after it is mixed with water and cured. This allows stains like rust and oil to penetrate down into the surface.
To remove these stains and get your concrete clean, you need something that will also sink in and lift the offending spot. Cat litter, sawdust, baking soda, and other absorbent materials remove fresh spills, but don't do much about what sinks into the surface.
Muriatic acid is sometimes used to clean concrete garage floors. But the binder in concrete, called Portland cement, dissolves when it comes into contact with an acid. Plus, acid-based cleaners pull calcium hydroxide out of the hardened concrete, which then quickly forms a white, dusty material called efflorescence. This material can become so heavy and visible that you'll need to clean it off of your floor.
Another cleaning agent that is widely believed to be the best way to clean a garage floor is trisodium phosphate (TSP). It is strongly alkaline, so it will not harm the concrete floor, but this also means it could cause skin irritation and even burns. TSP is also very bad for the environment. If it ends up in lakes and streams, the phosphates trigger an overgrowth of algae that results in a depletion of oxygen levels in the water, which can endanger fish and aquatic plant life.
Simple Green Oxy Solve Concrete and Driveway Cleaner can be used with a pressure washer or for manual cleaning of concrete surfaces including driveways, sidewalks, patios, and walkways. The non-corrosive and non-degrading formula utilizes the natural power of peroxide to provide high-performance cleaning. It removes oil stains, grease, grime, and most discolorations. Its biodegradable* formula is safe for lawns and pets.
Thoroughly clean your garage floor once or twice a year using the instructions below.