For dry areas, the weathering process can be accelerated by periodically wetting down the deck with a garden hose. Also, lower quality fasteners and other metal hardware objects can cause rust stains. These cleaners are readily available at lumber yards, home centers and hardware stores. Use conventional deck washes or cleaners containing sodium hypochlorite and detergent. Be sure the deck has gaps between boards to allow for water drainage, and that the substructure supporting the deck boards is level.
Barbeque grills are a major source of grease stains.
Other sources of grease stains may include salad oils, greasy foods, and oily residue on shoes or work boots. Remove grease and oil stains with a household degreasing agent as soon as the stain occurs. For stains that have set, a light hand sanding with a fine grit sandpaper works well. The sanded surface will initially become brown. This is normal and over time the sanded area will fade back to a driftwood grey hue.