First few minutes
Just happened? Do this first
- Keep the stain wet with the hose while you work.
- Rinse out every trace of cleaner before you move on.
- Don't let cleaner or soap dry on the boards.
- Test any cleaner on a hidden board first.
Deck stains run from dirt and mildew to tannin streaks and rust from nails, and each one needs its own treatment. Weathered, grayed wood can often be brought back with a deck cleaner, but if all the natural color has leached out, it will stay silver when dry. Old, peeling stain or sealer is a separate job that needs a stain and sealer remover, then a brightener and a light sanding once the wood is dry.
If you want to keep your current stain, clean the boards gently and skip the stripper completely. Cleaning a dirty deck without removing the existing stain is a lighter job, so rinse well to leave no residue. Oxygen bleach powder suits mildew on pressure-treated wood, and it's the product to try before anything harsher.
Before you start
What this material can take
Safe to use2
- Water
- Oxygen bleach
Use with care5
- Soaking
- Chlorine bleach
- Solvents (alcohol, spot removers)
- Acids (vinegar, lemon)
- Scrubbing and abrasives
9 items
What you'll need
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- Garden hoseFor the initial rinse, the mist and the final rinse.
- Plastic drop clothCovers nearby plants while you work. (opens Amazon)
- Mild dish detergentFor the first scrub in water. (opens Amazon)
- Stiff synthetic-bristle brushScrubs along the grain without scratching the wood. (opens Amazon)
- Household bleachOnly for the single dab test on black spots. (opens Amazon)
- Oxygen-bleach deck cleanerTreats mildew and organic growth on wood. (opens Amazon)
- Oxalic-acid wood brightenerTreats tannin bleed and rust streaks. (opens Amazon)
- Pressure washer with a fan tip (optional)Only at the lowest pressure that cleans. (opens Amazon)
- Oxygen bleach (opens Amazon)
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6 steps
Step by step
Step 1 of 6
Clear the deck and shield plants
Sweep off leaves and loose debris first so the cleaner reaches the boards. Cover nearby plants with a plastic drop cloth, then spray them with water to dilute any overspray.
Step 2 of 6
Start with a gentle scrub
Rinse the deck with the garden hose, then scrub with mild dish detergent in water and a stiff synthetic-bristle brush. Work along the grain of the boards, one section at a time.
Careful. Test any cleaner, and any pressure washer setting, in an inconspicuous area first.
Step 3 of 6
Check black spots for mildew
If the spots are black, dab a little household bleach on one of them, then rinse that spot well with the hose before going further. If that spot lightens, it's mildew, and the oxygen cleaner treatment will handle it, but never mix the two cleaners.
Careful. This is a single test dab, not a cleaning step, so keep the bleach off the rest of the deck.
Step 4 of 615 minutes
Apply oxygen cleaner in sections
Work an oxygen-bleach deck cleaner into one section at a time, and keep it wet for the label's dwell time of about 15 minutes. Scrub along the grain, then move on to the next section.
Tip. Mist with the hose if a section starts to dry before the time is up.
Step 5 of 6
Rinse before anything dries
Rinse the whole deck thoroughly with the garden hose so no cleaner or soap is left behind. If you use a pressure washer, set it to the lowest pressure that cleans, put on a fan tip, and spray with the grain.
Careful. Never let cleaner or soap dry on the surface.
Step 6 of 6
Brighten tannin and rust streaks
For reddish-brown tannin bleed or rust streaks, apply an oxalic-acid wood brightener exactly as its label directs. Treat only the streaks, and leave the brightener on for the time the label gives.
Careful. Make sure the oxygen cleaner is fully rinsed out first, because the brightener neutralizes it.
If you'd rather buy than mix
Best stain removers for decks & wood fences
Look for an oxygen-bleach deck cleaner for mildew and an oxalic-acid wood brightener for rust or tannin streaks. A stain and sealer remover is the product type for old finish, and it should be followed by the brightener.
OxiClean Versatile Stain Remover Powder
How we picked these: each product is made for this type of stain, its maker doesn't warn against using it on decks & wood fences, and its directions fit the steps above.
Finished the steps? How does it look?
Nice work. Let it dry completely and check it again in good light. Here is what done looks like:
How to tell it's really gone →A faint mark usually needs one more round, not a stronger product.
If the stain was already dried or set, the method changes.
Old, dried or set-in stains →When to call a professional →Know the stain? Use its own guide
Every stain on decks & wood fences
Paint, glue & adhesives2
Water, rust & minerals2
Oil & grease1
Discoloration & marks2
Smoke & burns1
Food & drink4
Ink, marker & crayon1
Wax, gum & sticky1
No match. Try the main search for anything else.
How to tell it's working
The wood should look evenly clean, with no dark spots left and no soapy film once it dries. If reddish-brown streaks remain after the oxygen cleaner and rinse, they usually need the brightener step.
What changes for yours
Adjust for your decks & wood fences
Trex, composite, and Azek decking
Start with the first two steps only: a hose rinse and a scrub with mild dish detergent and a soft brush. Leave out the oxalic-acid brightener, since it's a wood product.
If the stain doesn't lift, test the oxygen cleaner on a hidden board before using it across the deck. Keep the cleaner from drying and rinse it off fully.
Pressure-treated wood decks
Use the oxygen-bleach deck cleaner for mildew and the oxalic-acid brightener for tannin or rust, and skip chlorine bleach entirely. Chlorine bleach breaks down the wood's lignin and corrodes metal fasteners, so it's the wrong tool here.
Work one section at a time so the cleaner stays wet for its full time. Stick with the mildest treatment that clears the stain, and move up only when it doesn't.
Cedar, redwood, ipe, vinyl, kool, and boat decks
Cedar and redwood are soft woods, so skip power washing and caustic cleaners on them. The gentle scrub with mild dish detergent and the oxygen cleaner are the right tools, with the brightener only for rust or tannin streaks.
On vinyl, never aim a pressure washer upward and never use organic-solvent cleaners. For ipe, kool, and boat decks there's little specific guidance, so start with the mild scrub and test a hidden board before you move to anything stronger.
Old, dried or set-in stains
Old, weathered decks often clean up well with a commercial deck cleaner, brightener, or restorer, which removes mildew and dirt so the wood's own color can show. Old stain or sealer needs a stain and sealer remover first, then a neutralizing brightener and a light sanding once the wood is dry.
If the wood has gone dry and silver, the natural color has leached out, and the fibers should be left in place because no cleaner brings that color back. Tannin bleed and rust streaks respond to the oxalic-acid brightener used per its label.
Expect a stubborn stain to lighten rather than vanish completely. Check the result once the deck has fully dried before you try a second round.
Vinegar, baking soda, peroxide and more
Do home remedies work on decks & wood fences?
Most home remedies you'd reach for don't belong on a deck, so only a few make it into the steps. A few earn a spot on a deck, and the rest belong back in the cabinet.
Works2Skip4
Chemical safety
Never mix these
Some products in this guide react dangerously with each other. Use them one at a time and rinse with water in between.
Chlorine bleach + Oxygen bleach (OxiClean)
Both makers advise against combining them: OxiClean says not to mix it with chlorine bleach, and Clorox says the two bleaches cancel each other out.
If they mix by accident: Don't use the mixture; ventilate the room and avoid breathing fumes or touching it; call Poison Control at 1-800-222-1222 for disposal advice or if anyone feels unwell.
What makes it worse
Mistakes to avoid
Don't mix bleach with ammonia
Bleach mixed with ammonia, or with a detergent that contains ammonia, forms a toxic gas. Keep those products apart at all times while you clean.
Don't use chlorine bleach on pressure-treated decks
It breaks down the lignin in the wood, corrodes metal fasteners, and harms plants, and it doesn't kill mildew spores. The oxygen cleaner is the safer choice for mildew on these decks.
Don't bleach or wet-clean old CCA decks around kids and pets
Wetting raises the arsenic at the surface, and bleach releases chromate. Keep children and pets off wet CCA wood until it has dried.
Don't use narrow-stream or tornado tips
Narrow streams and rotating tornado tips are wrong for decks. Stick to a fan tip at the lowest pressure that cleans.
Don't power wash soft woods or scrub with caustic cleaners
Power washing soft woods like western redcedar removes wood from the surface, and caustic cleaners do the same when scrubbed hard. The gentle scrub and the oxygen cleaner are the safer tools.
Don't use steel wool or wire brushes
Leftover iron in the metal reacts with the wood's extractives and leaves dark stains. A stiff synthetic-bristle brush does the same scrubbing job without the iron.
When to call a professional
If your deck is old CCA treated wood and needs cutting or burning, leave that job alone, since the sawdust and smoke contain arsenic. Replacing the boards is the safer route. A pressure washer can also damage a deck in the wrong hands, so bring in a pro if you aren't comfortable with the settings.
Questions
Is it better to stain or seal pressure-treated wood?
Cleaning alone doesn't settle stain versus seal, so the safe move is to clean first. Let the wood dry fully before you choose a finish, and test your choice on a hidden board.
How do I keep a stained deck clean?
Sweep off leaves and debris regularly, and rinse the boards with the garden hose so dirt doesn't sit. Use the gentle scrub with mild dish detergent for light grime, and reach for the oxygen cleaner only when mildew shows.
Can I clean a deck without removing the existing stain?
Yes. The gentle scrub and the oxygen cleaner remove dirt and mildew, and the stain and sealer remover is only for old finish you want gone.
How do I get rid of an old, peeling stain?
Use a stain and sealer remover on the old finish, then neutralize it with a brightener. Lightly sand the wood once it's dry.
Can I clean Trex decking the same way?
Yes, start with the gentle clean and skip the wood brightener. Test any cleaner on a hidden board first, since composite needs the mildest approach you can use.
Can I use bleach on a pressure-treated deck?
No. Chlorine bleach breaks down the wood, corrodes metal fasteners, and doesn't kill mildew spores, so the oxygen cleaner is the better choice.
Related
How we know this
Every method, amount and warning here comes from university extension services, industry bodies and product makers. We read them, check every step for unsafe combinations and changed amounts, and write it up so you can follow it.