One of my pet peeves is seeing a driveway with streaks and discoloration from improper cleaning techniques. If you do it yourself, or hire someone, its important to know how to clean it to prevent discoloration and striping, and how to make it stay cleaner longer. First, do not attempt to clean it with a tip alone. Go spend a little money and get a rotary surface cleaner from Home Depot, Lowes, ect. You can find a consumer grade for under $100. Not only will it cut your time down significantly, it will give you a more consistent cleaning pattern.
Ok, so tools needed:
Pressure Washer (ideally at least 3000 psi by 3 gallons per minute)
Rotary Surface Cleaner
Pump Spray Bottle
3 Gallons of 8% Bleach
High Pressure Hose and Lance
Downstream Chemical Injector
Dawn Soap
So lets get going.
Dump 1 gallon of bleach in a 5 gallon bucket, put about a shot of dawn soap then add about 2 gallons of water. Make sure you mix up well. Place the suction of the downstream injector in the 5 gallon bucket and begin to "pre-treat" the driveway by using the appropriate soap nozzle. Spray an even pattern and go ahead and treat the entire driveway all at once. Once your driveway is full of your soapy bleach mix, you are ready to begin. Attach the surface cleaner to the end of the pressure washer and trim out a section that you are ready to clean. When you begin cleaning it is important to clean in a manner that is equal to all portions of the surface (no overlapping and try and avoid staying in 1 spot to long). My suggestion is to go longways and sideway like a grid pattern. The other option is to go in circles from left to right, but I find the grid pattern to be easier, and better. Once you are finished with the surface cleaner, it is time to rinse and fine tune you work. Always know what direction your water is draining and work with it, not against it. While rinsing make sure you knock out any areas that you might have missed, or troublesome areas that did not clean as well. Ok, so the driveway is rinsed thoroughly and you have removed as much from the surface as possible; but you still have some sap stains, algae stains, smashed acorn stains.... This is the part that most people do not do - the post treat. Get that last gallon of bleach and put it in a pump sprayer, then add 1 gallon of water 1/1 ratio. Spray the entire driveway with the pump sprayer, and apply as needed where organic stains still exist. PUMP IT UP AS HIGH as possible. On the bad areas the more pressure you can apply, the higher your chance of removing will be. For areas that are still not coming clean, you can try using straight bleach. Remember, bleach is only going to remove "organic" stains - not hydrocarbon/oils.
So there you have it. Pre-treat, clean, and then post-treat. Your driveway will look brand new, and just as important it will stay that way for years to come.
Oh, another great solution is to............. CAll GEAUX FLEAUX!!!