If you live in a place that will have a surplus of snow within the next few months--like I do--you just might want to try this old time method of cleaning area rugs. Apparently, it works for wool, cotton and polyester rugs. Note: You'll want to use DRY snow for this procedure, not the soggy stuff.
1. First, if you can, vacuums the front and back of your rug, or gently shake it out.
2. Take your rug outside in a protected area and let it get acclimated to the outside temperature.
3. Lay the rug right side down in fresh, dry snow.
4. Beat the back of the rug with a broom or rake to create vibration, but don't mash the rug into the snow.
5. When you run out of steam, flip the rug over and check out how much dirt is left in the snow. If there's a lot, you might want to repeat steps 3 & 4.
6. When you’re satisfied with the cleanliness of your rug, gently shake or beat the back of the rug to get as much snow out of it as possible.
7. Take the rug back to the protected area outside and let it 'sublimate', letting the solid snow turn to vapor (ice) without it turning into a liquid (melting). This can only happen in very cold and dry conditions.
8. Take the rug back inside the house and let it return to room temperature before you place it back on the floor.