The type of carpet you’re cleaning matters a lot, but a subtle scent is possible most of the time. A faint scent is very common with wool carpets, and odors should fade away after an hour. Heat, humidity, and air circulation affect the time needed for the scent to go away. The cleaning method is essential. Some professional cleaners don’t use soap in the rinse water, so the carpets are fresh and clean, and don’t wear any odor from the cleaning products.