We use this stuff on our work boat, http://www.amazon.com/Star-Brite-Spi.../dp/B00EYNNNVW
. it brings any and every stain off, we have a bunch of spider poo to contend with and we manage to keep our white fiberglass hull looking perfect. Have not used it on vinyl. Make sure you rinse with plenty of water. I didn't rinse well enough and a week later three dry suits that were laid in an area we sprayed melted through over night. A very costly mistake.