Concrete is one tough material, but cleaning it can be tricky. Concrete is a tough but porous material that can easily hold dirt and grime. But by applying a sealer to fresh concrete or after cleaning concrete surfaces, you can keep it looking new for years to come. To clean older concrete, use a pressure washer along with an application of mildicide. The mildicide kills fungus that detracts from the concrete's surface and the pressure washer blasts years of grime away. Cleaning concrete is an easy way to spruce up the outside appearance of your home.