The answer to 'carpet stained' is that there are several common causes, including spills, tracked-in dirt, pet accidents, and general wear and tear. Symptoms may include visible stains, discoloration, or an unpleasant odor. Solutions can range from DIY spot cleaning to professional deep cleaning, depending on the severity and cause of the stain.
For small, fresh stains, you may be able to treat the area yourself using a carpet cleaner solution and a clean cloth or sponge. Blot the stain gently, don't rub, and be sure to follow the product instructions. However, for larger or set-in stains, it's best to call in a professional carpet cleaning service. They have the right equipment and cleaning solutions to effectively remove stubborn stains without damaging the carpet fibers.