How to clean bird droppings off artificial grass without spreading them

Bird droppings are urine and feces together. The white part is uric acid, which is what makes them corrosive on paint and bonds them to a fiber as they dry. The dark part is digested food, and in the warmer months on the coast that means mulberry, pokeweed, wax myrtle and whatever else is fruiting, which is where the purple and red stains come from. Fresh, the whole thing is soft and rinses off a polyethylene fiber. Dried in the sun, it sets hard and the pigment migrates into the fiber surface, and the longer it sits the more of the pigment stays.

Hose on a shower setting, aimed to push it off the turf toward a bed or the drain rather than across the lawn. That is the whole job. If you have a roost or a feeder over the turf, this happens daily, and the section on prevention at the bottom is the one that matters.

1. Put gloves on. Dried droppings can carry organisms that become airborne as dust, so wet everything before it is disturbed.
2. Soak. Lay a wet rag or paper towel over the spot and leave it ten minutes. The crust rehydrates and loses its grip.
3. Lift. Slide a plastic scraper or an old credit card under the softened crust and lift straight up. Do not wipe sideways; it smears into the neighboring fibers.
4. Treat. Spray an enzyme cleaner labeled for pet turf, or a mild dish-soap solution, and let it sit five minutes. The enzyme breaks down the uric acid left in the fiber.
5. Brush lightly with a soft synthetic brush, with the grain.
6. Rinse thoroughly and let it dry.

If a purple or red mark remains after the dropping is gone, the pigment has set in the fiber. Apply the enzyme cleaner again, keep it damp for an hour, brush and rinse; two or three rounds fade most of it. If it survives that, test three percent hydrogen peroxide, the drugstore kind, on a hidden corner of the turf first. If it does not lighten the fiber color after ten minutes, apply it to the stain, wait ten minutes, rinse. Peroxide is a mild oxidizer and is safe for most turf, but older, sun-faded turf can lighten, which is why the test comes first. A stain that has baked for a month on old turf may be permanent; the fiber is still fine, the color is not.

• Scrape it dry. Grinds pigment in, breaks fibers, makes dust.
• Bleach. Lightens the turf around the spot so you trade one mark for a bigger, paler one.
• Pressure washer. Blows the dropping and the infill across the yard.
• Wire brush. The stain goes; so do the fibers.

Droppings land in patterns: under a feeder, a pergola beam, a power line, a roost in the live oak. Move the feeder off the turf, and if a branch is the roost, a trim solves a season of cleanup. Turf under a wire is a rinse-weekly situation. For a yard that has collected a summer of set droppings and berry stains, the fix is a power brush, a high-volume rinse and a deep stain treatment, which we do as part of our stain removal at $75 to $150 as an add-on, or inside a Premium Restoration from $299 for up to 500 square feet. The dish soap page covers the mild solution used above, and the disinfecting page covers sanitizing a play area afterward.