The answer to 'upholstery smells bad' is that there are several common causes, including food spills, pet accidents, moisture buildup, and general wear and tear. Symptoms may include a musty or sour odor, discoloration, and even mold growth. Solutions can range from DIY cleaning to professional deep cleaning, depending on the severity of the issue.
For minor odors, you can try spot cleaning the affected areas with a mix of warm water and mild detergent. Blotting the area with a clean cloth and allowing it to fully dry can help. For more stubborn smells, you may need to steam clean the upholstery or use a specialized upholstery cleaner. If the odor persists or the upholstery is heavily soiled, it's best to call in a professional cleaning service to thoroughly clean and deodorize the fabric.