Patio stones are outdoors and exposed to human traffic, so they are susceptible to dirt and spills. If not cleaned up right away, spills can stain the porous stone, which results in a less attractive patio area. There are several methods of cleaning the stones and removing stains from the surface.
Hose down the patio stones with as much water pressure as you can generate. Use a pressure washer if you have one.
Apply oxalic acid to rust-stained areas. Follow the directions on the label for use. Rinse the area well when done, and use towels to block water from running off the patio and into the plant areas.
Scrub food stains with a scrub brush and soapy water. Use a oil-fighting liquid soap. This will lift out grease stains and clean the surface. If the stains don't come up with the basics, try using a baking soda paste. For stubborn grease stains, mix plaster of Paris with water as is directed on the package and add a teaspoon of dish soap. Spread this mix over the grease stain and let it dry. When it dries it will be crumbly, and you can sweep it up. The plaster of Paris will pull the grease out of the pavers.
Clean with vinegar and water to get rid of vegetation stains such as algae, moss or leaves. Let the solution sit for 15 minutes and then scrub with a brush.