10 Best Composite Deck Cleaners 2026 in the United States

The 30 Seconds Outdoor Cleaner is designed to quickly remove moss, algae, mold, and mildew stains from various outdoor surfaces including composite decks, vinyl siding, patios, and fences. Its cleaning power is strong enough to tackle organic growth effectively, which is great if you want a fresh, clean look without harsh scrubbing or pressure washing.

The product is safe to use around lawns, trees, and shrubs when you follow the directions, so you don’t have to worry about damaging your landscaping. Application is simple — you just attach the hose-end sprayer to the bottle and spray the affected area, then rinse off. This method is convenient and saves time compared to using a pressure washer or scrubbing by hand. It covers about 900 square feet per bottle, so it’s suitable for medium to large outdoor cleaning jobs.

Compatibility-wise, it works well on a variety of surfaces including wood, concrete, brick, plastic, and vinyl, making it versatile for many outdoor cleaning needs. The concentration is balanced to provide strong cleaning without leaving harmful residue, supported by the safety claims indicating it rinses off cleanly. The product comes in bottled form with a hose attachment, so you need access to water and a hose for best results. This cleaner is a practical choice for homeowners looking for an easy, safe way to remove organic stains from composite decks and other outdoor surfaces without needing special equipment.

Wet & Forget Outdoor Stain Remover is designed to clean composite decks and other outdoor surfaces by gradually breaking down moss, mold, mildew, and algae stains without scrubbing. Its cleaning power is gentle and works over time, typically removing green stains within a couple of weeks, but tougher black or long-standing stains may take several months or even up to a year. This slow action means it’s great for people who prefer a low-effort solution, but it’s not ideal if you need immediate results.

The product is safe to use since it’s bleach-free and non-acidic, reducing the risk of damage to composite decking materials. Its hose-end applicator with a long 30-foot spray range and fan tip makes applying the cleaner easy and convenient, covering large areas without direct contact. Because it’s a liquid concentrate, one bottle can treat up to 2,000 square feet, though heavily stained or porous surfaces might need more product.

Another plus is that it requires no rinsing after application, saving time and effort, but you do need to apply it on a dry day with moderate temperatures and no rain expected for a few hours. One minor downside is that the product leaves no residue, so repeat applications may be necessary for tough stains, and it should be applied carefully to avoid nearby water bodies. This cleaner is well suited for homeowners looking for a safe, hands-off way to maintain composite decks and outdoor surfaces over time rather than quick spot cleaning.

The RMR-86 Instant Mold and Mildew Stain Remover Spray is designed to quickly tackle stubborn mold and mildew stains without the need for scrubbing, making it convenient for users who want an easy cleaning solution. It’s a ready-to-use liquid spray that works instantly to remove discoloration, which is especially helpful for deep stains that often appear on composite decks and other outdoor surfaces.

One of its strengths is versatility—it’s safe to use on multiple surfaces like wood, vinyl siding, concrete, and brick, so you can rely on it in various areas around your home. Because it’s a professional-strength formula, proper ventilation and protective gear are recommended during use to ensure safety. The spray has a fresh scent and doesn’t leave behind noticeable residue after cleaning, which means less rinsing and cleanup afterward.

Although it’s not specifically labeled just for composite decks, its compatibility with common deck materials makes it a suitable choice for deck maintenance. The main drawback is the need for caution during application due to its strong chemical nature, so it might not be ideal for those looking for a gentle or eco-friendly cleaner. For fast, effective mold and mildew stain removal with minimal effort, this product is a strong option.