Originally Posted by Magic Bus

Show, there was a thread on this forum about a month or two back. I believe the answer was that it's from bees and the pollen their carrying falls. I have a PW G35 and that yellow stain has happened to me on numerous occasions. Immediate washing/cleaning or detailing does not remove it. However in a week or two, it just goes away. I know that sounds strange, but if you look at my G35 there are no yellow stains.