My 2012 Corolla has these little green rocks that appear on the passenger floor board. I cleaned them out a few weeks ago and now they are back. No one rides over there ever and there is nothing ever set over there or anywhere in my car. I drive it to work and back and that is it. These weird rocks look like fish food or maybe something from a filter?? I also seem to have a weird rattle in my dash. Am I going crazy or are these things falling from under my dash... out of the lower vents..some kind of insulation that is breaking free? The car was bought new. Its not like its making a mess its maybe 6-8 every few days. It is just the fact of the matter and it is quite curious.