If your driveway looks dark, stained, or slippery when wet, it’s time for a cleaning. Over time, oil leaks, mold, mildew, and dirt accumulate on concrete, making it not only unattractive but also unsafe. In Raleigh’s humid climate, most homeowners benefit from having their concrete surfaces cleaned once or twice a year to keep them looking fresh and prevent long-term discoloration or erosion.