This was my initial thought. The carpet cleaner. Maybe to clean up the location where soiled evidence was placed?
Good catch! For some reason, I assumed her truck had been parked at Walmart for much of the time. There was such an overwhelmingly crazy amount of detail in the video and I literally forgot this. It sounded weird as soon as I heard it initially, but he said so many nonsensical things, that one slipped my mind. This is why con men speak many words, yet say very little. It actually works, in spite of ourselves. IMHO