My girlfriend cleaned my carpet using a carpet shampoo machine. I placed all of the removable pieces on the concrete driveway and first sprayed them with an aerosal carpet shampoo (Blue Magic?)and let them sit for a while. Then she used the machine on them. It sprays a water/shampoo solution on the carpet, brushes it with a rotary brush, and then vacuums up excess moisture. She also did the fixed pieces in the car and the seats using a furniture attachment that came with the machine. It worked pretty well. Lots of dirty water came up from the pieces.
She does good work! She even did my Nissan pickup interior!
Mike