Minnesota is a unique and wonderful market for carpet cleaning. Everyone wants carpet on their floors because the floor gets too cold in the winter and it helps keep our toes warm and heating costs down. However, our de-icing methods and sanding the streets, not to mention mud during the spring thaw, contribute to Minnesota being one of the harshest climates on carpet.
The sand we use makes ice less slippery but that same grit that makes our tires and shoes gain traction also acts like sand paper on the bottoms of our shoes.
When salt is allowed to build up in a carpet (commercial carpet more likely), it will form together into a single mass. Especially when moisture like melting snow is added. This mass not only adheres to the fibers but now has a much larger surface area to get through. For this a portable carpet cleaning unit and dry cleaning methods are useless. The salt needs to be melted through moisture and heat. It then needs to be removed through large amounts of suction. I recommend a top of the line direct drive truck mount unit. (Hydramaster 4.8 cds if possible). For best results have the carpet cleaned on a regular schedule before the salt has a chance to combine with itself and the sand. Also vacuuming regularly is helpful to get as much out as possible while still in crystal form.