Guys and girls, I was at a survey this morning in a large farm house conversion. They had crimson red polypropylene carpets throughout. At many areas near the carpet edges, there was a light blue residue, almost like dust. This only seemed to be next to the glass doors on the outside of the building, nowhere else? Also, when I wiped my hand over the carpets, a fine red powder was coming off the carpet??? I'm guessing the light blue residue was originally red and has maybe been faded by the sunlight?? The customer said the carpets had never been cleaned before, only hoovered. My gut feeling is that they will clean fine, but i'm curious to know what has caused the powdery residues? Any ideas???