If your rugs are not smelling fresh due to pets, dampness, or other conditions, you can freshen them up without any chemicals. Simply fill a container with 1 cup of cornstarch and 1 teaspoon of ground cloves. Shake well. Sprinkle all over carpeting and let sit for 20 minutes. Now vacuum. The odor will be absorbed by the cornstarch while the cloves leave behind a homey scent. (Always spot-test before using).