Even with the worst stains I've had (coffee that had been layered a lot and set in for years) I've had success with all the cleaners I've tried, Turtle Wax, Scotchgard, Blue Magic, and Tuff Stuff. I got all of those when I left Advance in East Stroudsburg because I still got my discount and knew I'd need a lot of it. In both Contours and the SVTF they all work awesome, the key is scrubbing with a very stiff bristle brush, that will get everything out.
Lately I've been looking at a small steam extractor which are around $100 on Amazon, I talked to my cousin who runs his own detailing business because he has a small one like the ones I've been looking at and he told me they work very well. He had to upgrade to a commercial unit, but not because it cleaned any better, simply because of the volume of work he does, the little ones are great for a DIYer like me, but for pro work they take too much time having to empty and refill the reservoir.