Don't laugh, I'm serious... Take glass plus (or any similar) spray directly onto the carpet in the area you want to clean, very librally. Let sit for a couple of minutes and scrub with some sort of short bristled brush. I use one of those kitchen types that has a looped handle over the top that you can slide your hands through. Once you are done scrubbing, work it in / rub it off, with an old towel. You'll be surprised. I just did this the other day to my daughters car with light gray carpeting and it came out well. It removed the dirt and salt stains. You know how brown dirt stains look on light gray carpet? Gone! Also, I did her carpeted floor mats. Put flat on the ground after vacumming, and with a hose, the same brush and any household cleaner like Mr clean and good old elbow grease. Finally, I hosed it off really well, and hung in the basement to dry. I couldn't believe how nice they came out.
Folex works wonders. You can find it any Safeway or Giant and most of your Home Depot's. Just follow the directions
