Best Deck Cleaners & Brighteners

Three kinds of cleaner, three different jobs

Every "deck cleaner" on the shelf is one of three chemistries. Match the chemistry to your problem and you'll cut cleaning time in half.

• Sodium percarbonate (oxygen bleach). Wood-safe, breaks down into water and oxygen. This is the workhorse for pre-stain prep, mildew, and general grime. Products: Restore-A-Deck Cleaner, Defy Wood Cleaner, OxiClean Versatile.
• Oxalic acid (wood brightener). Removes iron and tannin stains, neutralizes alkaline cleaners, restores the wood's pH so stain penetrates evenly. Products: Restore-A-Deck Brightener, Defy Wood Brightener, Cabot Wood Brightener.
• Sodium hypochlorite (chlorine bleach). Kills mildew and mold, but degrades wood fiber. Use only for stubborn black mildew on painted or capped composite surfaces — not on bare wood before staining.

The proper deck-cleaning sequence

1. Sweep. Blow off leaves and gritty debris — grit is what scratches the boards under a brush.
2. Wet the deck with a garden hose and cover any nearby plants with plastic sheeting.
3. Apply percarbonate cleaner with a pump sprayer. Let it dwell 15–20 minutes; don't let it dry.
4. Agitate with a stiff-bristle deck brush, moving with the grain.
5. Rinse thoroughly. If you see foaming still coming off, rinse again.
6. While the deck is still damp, apply oxalic acid brightener. Let it dwell 10–15 minutes.
7. Rinse a final time. Let the deck dry 48 hours before staining.

Best products by job

• Best pre-stain cleaner: Restore-A-Deck 2-part Kit (cleaner + brightener). Formulated together, no measuring, results are consistent.
• Best general-purpose cleaner: Defy Wood Cleaner. Widely available, works on wood and composite.
• Best for composite: Corte-Clean or Wet & Forget Outdoor. Composite doesn't need brightening — just mold and mildew killing.
• Best mildew killer: Wet & Forget Outdoor. No-rinse, no-scrub, kills mold for up to a year. Slow-acting (results over 2–4 weeks) but zero effort.
• Best budget option: OxiClean Versatile + Home Depot Oxalic Acid Wood Bleach. Same chemistry as branded kits at 40% less cost.

Composite decks — different rules

Composite doesn't need brightening (there's no wood to open the pores of), but it does grow mold in the tannin residue that leaves collect. For capped composite, a soft brush + soap and warm water handles 90% of cleaning. For stubborn mildew, use a composite-specific product — never a pressure washer above 1500 PSI, which will damage the cap.

Tools you'll actually need

• 2-gallon pump sprayer (for even application)
• Stiff-bristle deck brush with a threaded pole (fits any painter's extension)
• Rubber gloves and eye protection (both cleaner and brightener sting)
• Painter's plastic to cover plants and siding

What to skip

• Pressure washer above 1500 PSI on any wood — it will splinter and etch the boards.
• Chlorine bleach on bare wood — it breaks down lignin and leaves the surface fuzzy after drying.
• All-in-one cleaner/brighteners for pre-stain jobs. They work for casual cleaning but don't neutralize pH deeply enough for a stain job.

Budgeting the job

Materials for a full clean + brighten of a 200 sqft deck: around $60–$100 (cleaner, brightener, brush, sprayer if you don't own one). Contractor cleaning: $200–$500. See your specific numbers in our deck cleaning cost calculator.

Bottom line

For most homeowners, a Restore-A-Deck 2-part kit in early spring plus a mid-summer soap-and-brush touch-up will keep any deck looking new. Skip the bleach, use the brightener even if the label says "optional," and don't forget the 48-hour dry window before you stain.