Over time, grit and dirt become embedded so deeply that professional cleaning is required. Professional cleaning will remove this dirt as well as the surface soiling that gradually dulls the appearance of a rug.
Vacuuming
Occasionally, you should also vacuum the back of the rug to draw out the very short, light-absorbing bits of yarn that can otherwise dull the luster of the carpet. This operation should be followed by a quick vacuuming of the face of the rug.