I moved into my house five years ago, and I haven't really done any exterior cleaning. I have brick, siding, and some wood surfaces, plus sidewalk. It all looked nasty after five years of neglect ( you can see some "before" pictures below.)
I called Hal Hayes at Ultra Wash and hired him to clean the house, and he did!
He did a great job at my front door, and the back door, and also scrubbed the sidewalk, patio and driveway.
You can hire Ultra Wash yourself by calling 251-366-5291. And more info is available at ultrawashmobile.com
Take a look at the before and after pictures below-