we vacuum really well first....then rinse a bunch of times.....then take the vac hose off the wand and soak the areas. clean the other non salted areas...go back clean the area again....and repeat steps if needed. Warn custys that you may have to come back to reclean salted areas because some residue may still be in the carpet and needs to be rinsed a second time.
The problems we have had in recent years are not so much with the salt. But with the "speedy ice melters". These new products seem to give off and oily/sticky residue that gets on the entry ways of carpets and can cause a rapid resoiling, and or rapid soiling of the carpet if not fully rinsed out. Put your bare hand in one of these back of ice melters, your hands will have a slippery greasy film on them.