Prep first
Before you start
- Mist the droppings with water before anything else.
- Put on gloves before you touch them.
- Seal the wet mess in a container for disposal.
- A large build-up is a job for a professional cleaning company.
Bird droppings on a deck are highly acidic, and dry droppings turn into dust that you don't want to breathe. Built-up droppings carry a fungus linked to histoplasmosis, so keeping that dust down matters as much as the stain itself. Weathered gray boards may never return to their original color, because natural color can leach out of the wood for good.
When you remove bird poop stains from a deck, wet the boards before you touch the dried droppings, so the dust stays down. On a painted deck the same rule applies, and an oxygen bleach powder is the product to reach for if the mark is set. If the droppings have sat for weeks, expect a second round, and stop if the wood starts to look pale.
Before you start
What decks & wood fences can take
Safe to use2
- Water
- Oxygen bleach
Use with care5
- Soaking
- Chlorine bleach
- Solvents (alcohol, spot removers)
- Acids (vinegar, lemon)
- Scrubbing and abrasives
7 items
What you'll need
Tap an item to get it on Amazon, or tick what you already have.
- Garden hoseWets the droppings and rinses the deck.
- Disposable glovesKeeps droppings off your hands. (opens Amazon)
- Sealable container or heavy bagsHolds the wet mess for disposal.
- Mild dish detergentThe base cleaner for the scrub. (opens Amazon)
- Stiff synthetic-bristle brushScrubs along the grain. Steel and wire brushes are out. (opens Amazon)
- Plastic drop clothProtects nearby plants. (opens Amazon)
- Oxygen-bleach deck cleanerTreats mildew or organic growth on bare wood. (opens Amazon)
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7 steps
Step by step
Step 1 of 7
Mist the droppings with water
Spray the droppings with water until they're soaked through, and add a little mild dish detergent to the water if you have it, since that may cut the dust further. Keep misting as you work so nothing dries out and blows into the air.
Step 2 of 7
Bag the wet droppings
Put on gloves, then scoop the soaked droppings into a container you can seal. Seal it right away and dispose of it, rather than leaving it sitting out.
Step 3 of 7
Shield plants and clear debris
Sweep away leaves and loose debris, and lay a plastic drop cloth over nearby plants. Spray those plants with water to dilute any overspray from the cleaner.
Step 4 of 7
Test the cleaner first
Pick a hidden spot, such as under a railing or along the back edge, and test the detergent mix there. If you plan to use a pressure washer, test its setting in the same place before you use it on the deck.
Step 5 of 7
Scrub with mild dish detergent
Rinse the section with a garden hose, then scrub it with mild dish detergent mixed in water and a stiff synthetic-bristle brush. Work along the grain so the brush follows the direction of the wood.
Careful. Don't use steel wool or wire brushes on exterior wood board products; leftover iron reacts with wood extractives and stains.
Step 6 of 715 minutes
Treat mildew with oxygen bleach
If the deck shows mildew or other organic growth, apply an oxygen-bleach deck cleaner to one section at a time. Keep it wet on the wood for about 15 minutes, then scrub along the grain.
Tip. Mist the section with a hose if it starts to dry, and move on only once it's clean.
Careful. Don't use oxygen bleach on painted surfaces.
Step 7 of 7
Rinse the deck thoroughly
Rinse the whole deck with a garden hose until no soap or cleaner is left on the wood. Then let it dry before you judge the result.
Careful. Never let the cleaner or soap dry on the surface.
If you'd rather buy than mix
Best products for bird poop on decks & wood fences
Choose an oxygen-bleach deck cleaner for mildew on bare wood, and check the label for the dwell time. Skip it on painted decks, and use a stiff synthetic-bristle brush for the scrub.
Amazon Basics Microfiber Cleaning Cloths
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.
Heavy buildup usually takes more than one round.
Heavy or long-standing buildup →When to call a professional →How to tell it's working
The spot is clear when the wood looks even and no droppings remain in the grain. If dark spots are still there after the wash, they may be mildew, so the oxygen-bleach step is the next move, not harder scrubbing.
What changes for yours
Adjust for your decks & wood fences
Painted deck
On a painted deck, skip the oxygen-bleach step, since bleach-type cleaners aren't safe on painted surfaces. Keep the wet-first start, the gloved bagging and the mild detergent scrub, and test the mix in a hidden spot before you use it across the paint.
If dark spots stay after the gentle wash, rinse them off fully and let the deck dry before you judge the result. Don't reach for a stronger cleaner to chase them, since the paint is what would take the damage.
Pressure-treated deck
Pressure-treated wood takes the same wet-first start and mild detergent scrub, but chlorine bleach is off the table entirely. Use the oxygen-bleach step for any mildew instead.
If you do pressure wash, stay at the lowest pressure that cleans, with a fan tip and strokes that follow the grain.
Cedar or other soft wood deck
Soft woods like western redcedar can't take a pressure washer, so the hose rinse and stiff brush are the whole job. Keep the scrub to mild dish detergent in water.
Skip anything caustic here, since aggressive cleaners can lift the wood's surface along with the stain.
Weathered gray wood
Weathered, grayed decks can be restored with commercial deck cleaners, brighteners or restorers, which remove mildew and dirt so the wood's own color shows. Use these after the basic wash, not in place of it.
If all the natural color has leached out, the wood will stay silver when dry, and those fibers should be left in place rather than chased with stronger treatments.
Heavy or long-standing buildup
Old droppings that have set into the grain need more than the basic wash, and a second pass with the same mild detergent scrub rarely changes much on its own. Start by rinsing the deck fully, then look closely at the stain to see whether it's reddish-brown or dark and speckled. Those two kinds need different treatments, so don't mix them up.
Reddish-brown streaks from tannin bleed or nail rust respond to an oxalic-acid wood brightener, used per its label. Rinse out any oxygen cleaner completely before you use it, because the brightener neutralizes oxygen cleaners and the two will work against each other. Give the wood a full rinse afterward so no acid residue is left sitting on the surface.
For old stain or sealer that has built up on the boards, use a stain and sealer remover, then neutralize it with a brightener so the wood isn't left reacting. Lightly sand once the wood is dry, and only then judge the color, since wet wood looks darker than it will when it's finished drying.
Vinegar, baking soda, peroxide and more
Do home remedies work on bird poop on decks & wood fences?
Most of the home remedies you'll see online come from fabric or kitchen cleaning, and most don't belong on a deck. Only a few suit a wood deck, and mild dish detergent along the grain is the one this stain needs.
Works2Skip4
What makes it worse
Mistakes to avoid
Don't dry-sweep or shovel droppings
Dry droppings break into dust that you can breathe in, so wet them first and then collect the mess. Working dry is how a simple cleanup turns into a dust problem.
Don't use chlorine bleach on pressure-treated wood
It breaks down lignin, corrodes metal fasteners and harms plants, and it doesn't kill mildew spores anyway. Use the oxygen-bleach step for mildew instead.
Don't pressure wash with the wrong tip
If you pressure wash, use the lowest pressure that cleans, a fan tip, and spray with the grain. Never use narrow-stream or rotating 'tornado' tips on decks, and don't power wash soft woods like western redcedar, since that removes wood from the surface.
When to call a professional
Large accumulations of droppings are a job for a professional cleaning company. If you're considering a pressure washer, be extra cautious, because a deck can be damaged in the wrong hands. Old CCA lumber should be replaced rather than cut or burned, since its sawdust and smoke contain arsenic.
Questions
Is bird poop dangerous to clean up?
It can be, mainly because dried droppings turn to dust and built-up droppings can carry the fungus that causes histoplasmosis. Wear gloves, wet the mess first, and keep the dust down throughout. For a large build-up, hire a professional cleaning company instead of doing it yourself.
What is the reddish-brown streak on my deck?
A reddish-brown streak is tannin bleed or rust from nails, and an oxalic-acid wood brightener is the treatment for it, used per its label. Rinse out any oxygen cleaner first, because the brightener neutralizes it.
Why does my deck still look dark after cleaning?
Dark patches that stay after the gentle wash may be mildew, so the oxygen-bleach step is the next thing to try. Rinse the deck fully and let it dry before you judge the result.
Can I use vinegar or baking soda on my deck?
No, you don't need either one. Wet the droppings with water first and never dry-sweep them, then scrub the deck with mild dish detergent along the grain and rinse it all away.
What if my deck is old and I don't know if it's CCA treated?
Treat it as CCA until you know otherwise. Keep children and pets off wet CCA wood and don't wet-clean it, because wetting raises surface arsenic. Ask a professional to check it before you scrub.
Can I sand the deck to remove the stain?
Only after an old stain or sealer has been removed and the wood is dry, and then only lightly. Sanding is for old finish, not for fresh droppings on bare wood.
Bird Poop on other materials
Other stains on decks & wood fences
Start from the bigger picture
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.