Thank you. i pretty much suspected all of the above. Too much pre-spray, too little rinsing and extracting. We are using Pro-chem Ultra prespray (or sometimes Citrus Max) and Zoom rinse. We're using those two specifically because that's what the guy was using that we bought the business from- he said he'd "tried them all", and he got the best results from those. He had consistent 5-star ratings, and thousands of satisfied customers, so obviously he was doing something right. We've been trying to duplicate his process but I feel it's not quite working for us. Most of what I learned in my CCT class, he didn't do. I want to do an excellent job for our customers, but I'm constantly having to fight my boss; he wants to do "only what the guy did"; while I want to go about it more "by the book", drawing on what I learned in class. "The guy" rarely vacuumed first, and he used the same product on every carpet; which makes me nervous since the main thrust of the class was the importance of knowing the type of carpet fiber you're dealing with, and adjusting your chemicals accordingly. So i don't know how much importance to place on "by the book" methods, as opposed to what was obviously working for the previous owner ( he very rarely got a call-back, maybe 1 a year). I would appreciate whatever feedback you all can give me on all of this.