I clean the outside of our house with bleach to remove dirt and mildew, it saves painting it. Use a bottle that hooks to the water hose, you may not need a bottle full of bleach. Get the bottle from a Hardware store or where they sell plants, Lowe's may have them.
No matter what type of siding you have on your home, routine cleaning is a worthwhile project. This is a page about cleaning your home's siding.
