I would use chlorine bleach and laundry detergent. You don't want to be mixing bleach with other cleaners because of the potential to release toxic chlorine gas. Use about 3/4 of a cup of bleach per gallon of water and maybe a couple or three of tablespoons of detergent. The detergent isn't so much for cleaning as it is helping things disperse. Work it in to the surface with a scrub brush on a stick and keep at it so the surface stays wet for 5-10 minutes. Then rinse well with fresh water. If you have one, a power washer works too. Just be careful with pressure and how close the tip of the wand gets to the wood, you don't want to do any damage. You could also use any cleaner meant for decks or fences, if you happen to have some of that around. Just rinse well after use.

OMG...I'd have been concerned when they landed that massive pile of debris on my porch roof! That needed to go into a large dumpster!

Hi Vith-- Thanks so much for your input. The owner of the contracting company just came over and we did a little walk around. He agreed to remove the vented vinyl soffit on the second floor, put up wood where the old rotted soffit was removed, cut ventilation strips over the course of the wood on the second floor --old and new--(he was upset that they hadn't cut ventilation into the old wood soffit wood, as instructed), cover the ventilation openings with screening to prevent access by animals and put the new vinyl soffits back up. He also agreed to replace any shingles that were chipped or cut when the flashing was put up and power wash any soiled areas of the house. This seems pretty fair to me. He was extremely apologetic about the confusion about the garage being included in the initial contract and about the fact that proper ventilation was not done on the old second floor soffits.I told him I just wanted to be sure that the amount of ventilation met the specs for the roofing material to avoid premature aging, roof failure, etc. What do you think?

use dalys house cleaner and then hit it with dalys wood brightner. use a stiff deck brush if you use a pressure washer it needs to be at a low pressure of 600 to 800 psi.