Mineral deposits on composite decking can be removed by several methods. It’s important to identify the cause of the mineral build up, since different solutions will work for each type of deposit. Once you have determined what is causing the mineral deposit problem, consider these ways to remove it:
Swipe with a power washer – A pressure washer removes loose particles and softens hard scales that are difficult to remove. To do this safely, wear protective clothes (long sleeves and pants) and goggles, not just because of splashing water but also flying debris! Also cover nearby surfaces so they won’t get damaged. Before using any chemicals or power washing your deck, rub some dishwashing liquid into areas needing cleaning then use the high-pressure spray to scrub the area clean.
Regularly check your deck – Regular direction with a pressure washer will help you avoid build up and keep your deck looking like new.
Abrasive cleaners – For mineral deposits that have been built up over time, it is best to apply an acidic cleaner that breaks down the scale on contact. Products specially designed for cleaning composite decks can be found at most paint and hardware stores such as Pro-tek Advance Deck Cleaner or Preval Sprayer . For small areas, use a brush to work the product in, then rinse with a garden hose. You’ll want to protect nearby plants by covering them before using these products. Be sure to follow all directions provided by the manufacturers of these products.
For those that have a hard time getting off mineral deposits I have attached a tutorial on how to do it using non-toxic and ecofriendly cleaning agents. You can also use this method for wood decks by just replacing the composite material with whatever type of wood you have on your deck.