One way to clean a concrete patio is with a detergent and water solution, mixing a few teaspoons of dish soap like Dawn or Ajax with a bucket of warm water. Using a stiff-bristle brush or mop, the patio can be thoroughly scrubbed, focusing on any dirty or stained areas. After letting the solution sit for 10-15 minutes, the patio should be rinsed clean with a garden hose.
Alternatively, a vinegar and water mixture can be an effective cleaning agent. By combining equal parts white vinegar and water in a bucket, the solution can be applied to the patio and allowed to sit for several hours to help break down tough stains. The area can then be scrubbed with a brush before rinsing. For particularly stubborn stains, undiluted vinegar can be used.
Oxygen bleach products, such as OxiClean, can also be a useful tool for brightening concrete and removing stains. These products should be mixed with water per the manufacturer's instructions, applied to the patio, and allowed to sit before scrubbing and rinsing.