The simplest way to avoid damage and staining is to protect your carpet from dirt, mold and sunlight. To do so, place mats at all entrances to trap dirt.
You may also make a rule that all residents and guests remove their shoes upon entry. Ensure all pets are clean and house trained before allowing them onto areas with carpet.
Enforce strict rules about bringing food and drink into carpeted areas, and clean up all spills immediately to inhibit mold growth. Finally, keep the blinds drawn when sunlight hits the carpeting directly, as ultraviolet light can bleach out color and damage carpet fibers.
Invest in a powerful, suction-only vacuum cleaner. Brushes are designed to fluff and agitate fibers, but they can fray and damage felted shag, reducing the longevity and attractiveness of the carpeting.
For areas with light traffic, vacuum the entire carpet once per week and vacuum high-traffic areas, such as doorways twice a week. For homes with heavy traffic, vacuum the entire carpet at least twice weekly and high traffic areas daily.
In areas where the carpet becomes heavily soiled, run the vacuum over it at least five times, but change the direction of the vacuum to ensure you remove all dust particles and lift the shag.
Address all spills and stains as soon as they happen. Blot any visible liquid with a clean, white cloth before treating the stain.
For drink stains from coffee or wine, clean with white wine vinegar before applying a spot treatment. For blood stains and other food stains, use a cold ammonia solution, as heat can set the stain.
After initial treatment, apply the manufacturer-recommended detergent solution and blot. Repeat until the stain is removed.
Rinse with water, blotting continually, and then vacuum any remaining fluid. Allow mud stains to dry completely before treating.
Break the stain apart with a butter knife and then vacuum the bits of dried mud. If stains remain, clean with a manufacturer-recommended detergent solution.
Steam clean your felted wool shag carpeting once per year or, at the very least, once every eighteen months. Your best option is to rely on professional carpet-cleaning services, as consumer steam cleaners may not provide the deep cleaning necessary to retain the quality of the felted wood shag carpet.
Aim all fans at the carpeting to increase drying time after cleaning. Invest in a good dehumidifier to expedite the drying process when the carpet-cleaning professionals have finished.
Note that deep stains will sometimes rise to the surface due to capillary actions while the carpet is drying. If this happens, contact your carpet-cleaning professionals immediately so they can identify and remove the stain.