Using a pre-treatment method and pressure washer to clean your concrete helps remove any tough stains such as mold, mildew, dirt, oil stains, etc. Believe it or not, grass, leaves, dust, debris, and spills leave marks on your concrete over time. It's important to remove dirt regularly from these surfaces to maintain that clean natural look. Dirty concrete can drastically shorten the lifespan of your concrete. Over time the bacteria and mildew can eat away at the integrity of your concrete causing cracks and setting the stage for the integrity of the concrete to be slowly eaten away.