After years of tracking mud and exposure to the elements, your once pristine concrete walkway might look worse for the wear. There are several effective concrete cleansers you can buy, although many contain strong acids and harsh chemicals that will harm or kill nearby grass. Instead, use the right tools and safe cleansers to clean the dirt, moss or mildew from your concrete pathway.
Sweep the walkway with a stiff-bristled broom to remove any dirt or debris.
Mix together 2 tablespoons mild dish soap and 3 gallons of warm water in a plastic bucket. Mild soaps contain no dyes or perfumes.
Spay the pathway with a garden hose to dampen it.
Dip the end of a stiff-bristled broom into the plastic bucket and scrub the entire surface of the concrete pathway. Use extra force to remove any tough stains or spots from the concrete.
Rinse off the concrete pathway with the garden hose. Take care to spray the concrete itself, not the grass. Allow the concrete to dry completely before checking for any stains left behind.
Spray the area with a power washer with a low-output, high-pressure nozzle. The Concrete Network recommends using a 3,000-pounds-per-square-inch power washer with flat-fan nozzle to remove the ground-in dirt or difficult stains from concrete. Keep the spray from the pressure washer off nearby plants and grass as the pressure washer can damage them.