Luster-Washed Wool Rugs: What You Need To Know

When rugs are woven often there is some additional work done to help create a particular finished look. With wool rugs, “luster washing” is a common treatment we see come into our rug facilities, and it is one to make note of in our pre-wash inspections.

“Luster washing” is a chemical wash to help give a wool rug more sheen. Using solutions that are often bleach based, the process dissolves the outer cuticle layers of the wool in order to make them smoother. This softens the colors, makes the wool softer to the touch, and makes the fibers have more shine like silk.

In fact, with extreme chemical work, these rugs are often mistaken as silk by consumers.

“Luster washing” done well creates a beautiful effect. These rugs can have a great shine and look to them. However, this process to add “luster” to the look has a cost.

The Price Of “High Sheen”

The chemicals in this process are removing the natural protective layers of the wool. Under the microscope the layered scales of wool become smoother with this luster wash work.

Electron microscope photos showing the impact of chemical luster washing to wool rugs. Published by Dr. Agnes Zsednai for WoolSafe News (December 2021 issue).

The unintended consequences of removing the outer cuticle layers is that this is also removing the natural strength, durability, and repellency of the wool. As a result, this makes the wool more susceptible to UV fading, more prone to permanently stain from spills, and more likely to wear from foot traffic.

The most familiar example of the consequences of a strong luster wash are Chinese hand knotted wool rugs woven in the 1980’s. These were rugs made with excellent wool and dyes, and given a strong chemical wash to create a heightened shine and soft feel to the wool.

This work was done on the surface pile of these rugs. This allows you to see exactly the impact on the wool fibers physically when you compare their chemically affected tips compared to the base of the fibers.

Grinning open the fibers during a pre-wash inspection will show fade and if the rug has been chemically luster washed.

This particular production on Chinese wool rugs is known to be very sensitive to sun fade. They are rugs that cannot be dried in the sun after cleaning or they will dramatically lose their color.

The original pink wool of this Chinese rug has faded to beige on the front side.

Due to the high sheen of these Chinese wool rugs, they can continue to look attractive even when they are especially dirty. This shine can hide damage that is occurring to the fibers, in particular fading of colors or pile wear. For professional rug cleaners, if you are not detailed with your pre-wash inspection, you might uncover some surprising problems.

This particular Chinese rug had not been cleaned for more than 7 years

A Chinese “luster washed” wool rug with years of soiling that is hiding some pre-existing damage. Sun fade areas are noted, as is an area where a plastic protector has caused damage. Layers of soil can camouflage problems on these rugs.

The wool had a strong shine despite the layers of “life” embedded in the fibers. It was important to prepare the owner for the fact that several areas of fade from the windows were going to become much MORE evident after the rug was cleaned. As well as to point out the fiber damage from the underside of a plastic chair protector which was used along the right side. The small plastic teeth on the underside of the protective mat cut away at the chemically-weakened wool.

Knowing that the rug is luster washed, and sensitive to fading and wear, these areas could be discussed before the wash proceeded to help manage expectations.

As expected, removing the years of soiling revealed ALL of the areas impacted by sun and use.

After washing the rug comes back to life with stronger color and shine, but also shows every area of damage much more clearly

Luster washed wool rugs are much more prone to creating pooling effects in traffic areas. The wool is less resilient so it will wear in incorrect directions, which can create shadowing due to the change in light reflection.

Often with Chinese rugs you see this particularly along the edges and in high use areas. The friction breaks away the lightest tips of the wool and reveals a slightly darker tone underneath. This can become a darker shadow in front of a sofa with regular foot traffic. The weakening of the wool can sometimes make the fibers develop distortion in traffic areas that has them laying in the wrong direction and creating color differences.

With stronger wool, pile distortion can often be corrected. With luster washed wool it is a bigger challenge to try to improve these areas because it is not just temporary distortion but fiber wear and damage.

On a luster washed wool rug years of traffic has led to fibers pointing toward the side rather than down with the natural grain of the weave. The change in reflection creates a strong light and dark difference in the color as a result.

It is important to be aware of how these rugs are being used in their setting to spot areas of concern BEFORE you reveal them with your great rug washing work.

What To Do To Protect The “Look” Of Your Client’s Luster Washed Wool Rugs

These rugs in open areas will wear faster, and develop shadowing (light/dark areas) as the tips of the fibers break away from years of wear. This means these rugs need to be regularly rotated to help even up this wear over time.

These rugs should have a fiber protector applied to help repel spills and soils so that quick clean up can be more successful and vacuuming can be more effective. It is the fine grit that cuts at the wool to cause wear, so regular vacuuming by owners of these rugs becomes especially important. A pad will also help act as a shock absorber to help slow down wear.

Window treatments to limit UV exposure to these rugs can slow down the fading process. Some wool protectors offer UV protection as well.

With the chemical wash having removed the wool’s natural repellency to spills, immediate clean up is more important than ever. Fiber protectors can allow more time to clean those spills up, and can help limit the permanent staining damage. You cannot bulletproof these rugs, but you can help buy an owner time to clean up with minimal damage.

Luster washed wool rugs are not able to repel spills so they are much more susceptible to staining. Fiber protector is especially important to recommend with these rugs to help add back some of the fiber strength stripped away by the luster wash process.

Clients need to be provided guidance to avoid grocery store spot and stain removers on these rugs, as many are not safe for use on wool. With these chemically weakened wool rugs these consumer products often create clean-up disasters.

In the past, luster wash work was performed only to the face side of these wool rugs. This made them easier to identify in an inspection process. The back side would be much darker than the front side. You could grin open the rows of wool and see that the tips of the fibers are lighter than the base. Like highlights in hair, you can see the original colors and the lightened effects chemically created.

Today with the popularity of “distressed” rugs chemical work is being performed to BOTH sides of rugs to fade the front and back. This aggressive chemical work is creating some new challenges for both rug owners and professional rug cleaners. We will dive into that topic in my next article.

Until then – happy rug cleaning!

– Lisa