That shit on the carpet is from the manufacture process I believe. It’s like super fine grey fibers. It resisted vacuuming to a great degree. Damn vacuum had little to no effect. I don’t know if it’s the carpet or what’s on it. I even tried a lint roller. No help. I finally resorted to some of the sound deadening mat, it worked pretty good by dragging it across the carpet, followed by a bit of vacuuming. I ran out of time for the front or even to finish the rear 100%.
I've used the adhesive side of duct tape or other very sticky tape with some success for stuff like that. Kind of a PITA though for a large area.