I use Folex for spot cleaning and Zep carpet cleaner for doing full interior carpet cleaning. I have a Bissel Little Green Machine that I use for extracting, along with my wet/dry vac.
I had a few stains that needed to be removed in the carpet of my car, and used some turtle wax carpet cleaner with bristle top, and got the stain out completely and left it looking brand new. I was very impressed with it for being $5 at autozone.