I’d start by treating it as a small safety job, not just a wiping job. Bird droppings can carry germs, and dried droppings can turn into dust if you brush them dry, so put on gloves and, if the mess is dry or dusty, a mask. Keep pets and kids away until you’re finished. Wet the area first with a spray bottle of water and mild dish soap. Let it sit for five to ten minutes so the dropping softens. Then lift it with a plastic scraper or a damp microfiber cloth—don’t use a stiff wire brush, because it can scratch paint, powder coating, plastic, or wood. Throw the waste into a sealed bag and put it in the trash rather than hosing it into a storm drain.
For the pollution film—soot, road grime, sticky residues, and general city dirt—I use a simple bucket of warm water with a few drops of mild dish soap. Wash with a soft brush or microfiber cloth, working from the top down. Rinse often and change the water when it gets dirty, otherwise you’re just spreading grime around. For sticky spots, a little baking soda paste can help, but test it on a hidden area first, especially on painted metal, stone, or treated wood. Avoid harsh bleach, ammonia, or abrasive powders unless the furniture manufacturer specifically says they’re safe. On wood, don’t soak the surface; use a barely damp cloth and dry it promptly. On metal, dry thoroughly afterward to reduce rust risk. On plastic and painted surfaces, gentle soap and a soft cloth are usually enough.
After the visible mess is gone, I disinfect the area with a product that’s appropriate for the material and, if it’s public furniture, approved by local rules. Let it sit for the label’s contact time, then rinse and dry. Good drying matters—especially on joints, seams, and metal legs—because leftover moisture attracts more dirt and can cause corrosion.
For routine upkeep, wipe high-touch surfaces weekly and spot-clean droppings as soon as you notice them. The longer they sit, the more they etch or stain. If birds keep targeting the same bench or table, move nearby food sources, cover the furniture when it’s not in use, or use physical deterrents rather than harsh chemicals. A quick rinse, a mild soap wash, and a dry cloth will handle most urban pollution without damaging the furniture or creating a bigger environmental problem.