Skip to content 
The fence is a standard white vinyl privacy fence with 5-inch-by-5-inch posts and flat post caps, installed about 6 years ago. The problem spots were on 4 posts along the back side of the yard, where birds liked to perch in the morning. By early August, I had 9 visible droppings stains: 5 on the tops and upper edges of the caps, and 4 running down the post shoulders.
These were not fresh droppings. The oldest were probably 3 to 5 weeks old, after a stretch of hot, dry weather with daytime highs between 88 and 96 degrees Fahrenheit. Fresh messes usually come off with a hose and a microfiber cloth. These had dried into crusty mineral-and-organic smears with a yellow-gray outline and a dull white center, which is typical when uric acid and dirt bake onto an outdoor surface.
2. Why Icy Hot and Flintstones vitamins sounded plausible for about 30 seconds
Icy Hot cream contains menthol and methyl salicylate in a creamy base. Flintstones vitamins contain vitamin C and various minerals, and once crushed they make a mildly gritty powder. If you squint, that sounds like “solvent plus gentle abrasive plus acid,” which is how a lot of DIY cleaning folklore gets started.
In reality, neither product is formulated for exterior vinyl cleaning. I knew that going in. But because the stains were already stubborn and I was curious whether the cream would soften the residue while the crushed vitamins provided a light scrubbing action, I ran a controlled little backyard experiment rather than smearing it over the whole fence.
3. How I set up the 14-day test
I picked 3 stained posts for treatment and left 1 similar stained post untreated as a comparison. On each treatment evening, I used roughly 1/2 teaspoon of Icy Hot cream and 1 crushed children’s chewable vitamin per post. I crushed the vitamin with the back of a spoon on a ceramic saucer until it was about the texture of coarse chalk dust.
I applied the cream first with a gloved finger, then pressed the vitamin powder into it to create a peach-colored paste. Each stain got rubbed for about 20 to 30 seconds with light pressure using a folded paper towel. I let it sit for 10 minutes, then wiped it off with a damp cloth. I did this once per evening, usually between 7:30 and 8:15 p.m., when the fence was no longer hot to the touch.
4. What the stains looked like before day 1
Before starting, I photographed and noted the stain sizes. The smallest was a speckled oval about 3/4 inch long. The largest was a drip-shaped streak almost 2 1/2 inches from top to bottom. On a simple visibility scale from 1 to 10, where 10 meant “obvious from 15 feet away,” most were a 6 or 7.
The discoloration had two parts: a raised crust and a shadow stain underneath. That distinction ended up mattering. Physical residue can often be loosened; ghost staining on vinyl is harder, especially after UV exposure and heat.