I got a great deal on 17 square of redwood bevel siding that sat in a guys yard for a few months. About 30% of it is showing slight stain from mildew I would guess. We tried a product from Home Depot that cleared it up really well but I need more of it. Is there a home made mix of bleach or something that will do the job cheaper? I am cleaning it off and pre-staining before I put it up.