A hand-knotted wool rug is a work of art -- a testament to the individual who crafted it. It's one-of-a-kind, and, as such, it should be treated accordingly. Oriental rugs are the hand-knotted woolen rugs that you see most often.
The natural oils in the wool repel stains; the colors don't run; and the rug should be hand-washed. However, wool rugs are heavy. A room-sized rug should be professionally washed every few years, depending on the amount of traffic it's experienced. A smaller, hand-knotted wool rug can be hand-cleaned and its nap returned to the shine it displayed when brand new.
The Dirty Test
Test the cleanliness of your rug by lifting a corner of it off the floor, bending it and examining the base of the fibers. If you see dirt, it's time to clean it. Another method is to rub over the surface of the rug with a damp, clean white cloth. If dirt transfers, it's time to clean it.
Vacuum or Shake First
If the rug is small enough, shake out the ground-in dirt. A vacuum will remove most of the dirt as well, but before you use it, turn off the rotary beater. Vacuum with the nap and be careful not to tangle the fringe in the machine. Turn the rug over and vacuum the bottom to catch residual dirt and grit.
To completely wash a hand-knotted wool rug, take it outside and put in on the driveway or patio. Thoroughly wet the rug with a hose and cool water, and hand-rub gentle wool cleaner into the nap. Using a large, soft sponge, scrub lightly in a linear motion, always going in the direction of the nap. Rinse thoroughly with the hose; then move the rug to a dry spot, preferably in the sun. A rotating fan helps the wool dry. If the rug is small enough, spread it over a slatted lounge chair to air out the underside. When the top has dried, turn it over to dry the back. Vacuum again to restore the nap.
Water is one of the best cleansing agents for a wool rug. A wet, color-safe cloth run over the nap should remove surface stains. Club soda is another safe spot remover; the bubbles lift and help remove a stain. Always blot the excess fluid from the rug. A light-duty machine also cleans the rug, but don't use a soapy solution. Mix 1/4 cup of distilled vinegar with a gallon of water to clean the rug, always cleaning in the direction of the nap. If the rug is on a wood or laminated floor, put plastic underneath the rug to protect the flooring. Dry the rug by propping it up from the underside and allowing air to pass over the weave. A hair dryer also works when drying a small spot.
Do not clean the fringe with anything except clean water. Bleach changes its color and destroys the fibers.