This was done off ladders, using a stand off.
Just a bucket of water with some fairy in it, use a couple of wet cloths and have a couple of dry ones in your bag.
When you get to brackets, slide them to one side and clean, then do the other side of the bracket, only takes a couple of seconds to do each bracket.
Try to include the soffit in your clean, makes a better finished Job all around, and dont price to cheap, off ladders can take you a couple of hours,