Reading labels on any product is not a pleasant experience, but a bit of research can save a lot of headaches down the road. Choosing the wrong product for the job can be a very expensive proposition. Case in point, deck cleaning products. After reading the deck cleaning product application instructions on several popular brands. it became quite apparent, most were not compatible with our metal balusters.
After consulting a rep from our local mom & pop hardware store, I decided to use their deck cleaning recipe; Mix 4 oz. TSP, one quart bleach, and one gallon of warm (to dissolve the TSP) water together. Wash the deck, rinse well. Wait three sunny days to ensure the deck is completely dry before applying the deck stain.
Note: Treated wood must be dry, I waited a year.. You can check the moisture content of the wood by spritzing it, if the water readily soaks in, the boards should be dry enough to stain . Also the homemade recipe was used on new wood, not wood that had been previously stained or weathered (checked or graying).