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My best guess is that the success came from physical softening and gentle abrasion, not any magical chemistry. The cream kept the dried residue moist for 10 minutes, which helped loosen the crust. The crushed vitamins added just enough grit to scrub lightly without immediately scratching the vinyl.
But bird dropping stains on outdoor plastic surfaces are more complicated than “dirt on top.” They can involve uric acid residue, mineral deposits, fine organic staining, airborne grime, and heat-set discoloration. A menthol cream and a sugary vitamin tablet simply are not targeted enough to break all of that down efficiently.
11. The safer methods that worked better afterward
After finishing the 14-day test, I cleaned the same posts with a much more sensible process: warm water, a teaspoon of dish soap in about 1 quart of water, a soft microfiber cloth, and then a melamine foam sponge used very lightly on the most stubborn spots. That removed more staining in 15 minutes than the DIY paste had in several evenings.
For the last faint marks, I used a diluted white vinegar solution at roughly 1 part vinegar to 3 parts water, let it sit for 2 minutes, and wiped again. On my fence, that final step cut the shadowing noticeably without harming the vinyl. If you try this, test a hidden spot first and avoid aggressive scrubbing that can burnish the surface.
12. What I would do first if bird droppings hit a vinyl fence in August
If the droppings are fresh, speed matters more than gimmicks. I’d hose them off within 24 hours, then wash with soapy water and a soft cloth. In hot weather, especially above 85 degrees Fahrenheit, baked-on residue gets harder fast and can leave a ghost stain if it sits for a week or two.
If they’re already stubborn, I’d start with a 5-minute soak using a cloth dampened with warm soapy water laid over the spot, then wipe, then repeat. Only after that would I move to a light pass with melamine foam or a vinyl-safe exterior cleaner. It’s less entertaining than vitamins and muscle cream, but much more effective.
13. Costs, time, and whether the experiment was worth it
In terms of materials, the experiment used about 21 teaspoons of Icy Hot over 14 days across 3 posts, plus 42 chewable vitamins total. Depending on brand and package size, that’s roughly $8 to $15 worth of supplies to partially clean a handful of stains. Time-wise, I spent about 12 to 15 minutes each evening between mixing, rubbing, waiting, and wiping, so just over 3 hours total.
For me, the value was in finding out, very clearly, that weird pantry-and-medicine-cabinet hacks can create a lot of work for very average results. As an experiment, it satisfied my curiosity. As a cleaning strategy, I wouldn’t repeat it.
14. My final verdict
So what happened when I rubbed Icy Hot cream and crushed Flintstones vitamins on stubborn August bird dropping stains on my vinyl fence posts every evening for 14 days? The crusty buildup softened, a few stains lightened, the fence smelled bizarre, and I ended up with only partial improvement.
If I had to score it, I’d give the method a 3 out of 10 for practicality and a 4 out of 10 for results. It was not completely useless, but it was absolutely not the hidden answer to bird-dropping stains on vinyl. If you want the short version from someone who actually tried it: save the Icy Hot for sore shoulders, leave the vitamins in the bottle, and clean the fence with products meant for fences.