Cleaning exterior siding?

[Herb]

I have shake type siding which is made of Masonite. Over the years,it
has deteriorated to the extent that power washing will blast it off the
house.
It's on te north side,and gets little sun,so mildew is present.
Is there a gentle spray that I can use,and just apply and hose down to
clean it?

[nowaczck]

They sell a cleaner at most hard ware stores. Use it with a power washer. Don't turn up the pressure to high.