There are several recommendations to cleaning your concrete driveway. One of the quickest and easiest ways to clean it is using a high pressure water washer. You can rent a heavy duty model with a wide sweeping tip and get the job done quickly and efficiently. Dirt and grime are removed amazingly quick. You can also use the washer on your patio furniture, fence, car, even your house! Use caution when cleaning wood or aluminum siding with a pressure washer as damage can occur to the siding and caulk from the high pressure spray causing water to seep in behind the siding. The high pressure washer will not remove all mildew, rust, oil, or paint stains on the driveway, however. You must treat these stains before or after the big wash.
If dark stains remain on your concrete after washing, test a small area by dampening the stain with fresh laundry bleach. If the bleach lightens the stain within a few minutes, the stains are mildew and can be removed with bleach.
Bleaching the mildewed surface is recommended. You can use a product called "Jomax" with a laundry bleach and water solution. "Jomax" is a mildewcide and this along with the detergent will activate the bleach, creating a much more effective cleaning tool. Use eye and skin protectors and cover all plants in the area with a plastic. Spraying water on the plants in the area before and after the application can avoid damage to them. Follow label instructions, and use the cleaning solution within 2 hours after you prepare it.