A lot of times it can appear to be this way when people use over-the-counter carpet cleaners. They leave behind cleaning solution that leads to areas becoming soiled faster. This makes it seem as though some areas of the carpet appear cleaner than others. Our recommendation would be to always contact a professional carpet cleaner using special spotters to remove stubborn stains rather than trying store bought methods. Our service provides a carpet protector that not only resists future stains, but makes vacuuming more efficient.