Concrete is popular for both indoor and outdoor floors. It’s durable and simple to clean but concrete can stain. This is because it is porous, and will soak up dirt, requiring regular but not too oftenm scrubbing to maintain its cleanliness.
A power washer is the easiest way to clean concrete outdoors. You should be able to blast away dirt, mildew and grime in an afternoon. Spray the patio surface with a detergent and use a stiff brush to scrub it into the concrete. Put on safety goggles and gloves. Turn on the pressure washer. Move the wand from one side, using the same motion as you would if you were mopping a floor.
Want to know how to remove stains from concrete? There are several options. You can use bleach, ammonia (Note: never mix the two) and other commercial solutions. For a natural solution to stubborn stains on interior concrete floors, mix flour and hydrogen peroxide into a paste the consistency of peanut butter. Spread it over the stained area. Let sit overnight. Then, scrape with a plastic-edged scraper tool. Trisodium phosphate (TSP) mixed with water and scrubbed onto the stained area with a nylon bristle brush can remove tough stains. Scrub till stain is gone and rinse with a hose. TSP is available at home improvement stores.
Muriatric acid can be used on outdoor floors to clean the toughest stains, like rust or dried grout. It’s a powerful, toxic material that should be used with extreme caution. Wear protective eyewear and gloves when using it and be sure to follow manufacturer instructions on how to clean concrete with muriatic acid.
For indoor concrete floors that are polished or stamped, you’ll need to take a gentler approach to how to clean concrete. You’ll just use a mop and a bucket of water mixed with a mild cleaner. Don’t use ammonia, bleach or any highly acidic substance on polished or stamped floors. Some good cleaners include Castile soap, liquid dish detergent, stone cleaners and mild floor cleaners. Mix a solution, apply to floor with a wet mop and then rinse with a mop dipped in clean water.
To make your concrete floors resistant to future stains, apply a concrete sealant. Use a paint roller to apply it to clean, primed concrete. Start in the middle of the area and roll the sealant out to the edges. Floors need to be resealed every two to three years. Knowing how to clean concrete properly will keep the floors in your garage, workshop and house looking good as new. Source: https://www.diynetwork.com/how-to/maintenance-and-repair/cleaning/how-to-clean-concrete-floors