Chemically Sensitive Rugs: Washing Treatments

This article was originally published in Cleanfax.

Last week, we discussed how rugs are cleaned with chemical solutions. This week, we will look at common chemical washing treatments.

Luster wash

The purpose of the “luster wash” is to make a rug have more sheen to it, and to soften the feel of the wool pile. The solution helps to dissolve some of the outer cuticle layers of the wool fibers to help them to reflect more light and have a softer touch. A light luster wash is given to most rugs before they go off to be sold. However, some countries give aggressive luster wash treatments in order to make the wool look almost silk-like in the way that it shines. Rugs woven in China and Pakistan can have a strong light/dark direction to them, which is maximized by these chemical treatments. Rug owners sometimes mistakenly believe their wool rug is silk due to this sheen.

How to identify luster washed rugs

Wool rugs that look like silk are a sign of a heavy “luster wash” processing. There is a very strong light and dark direction. When you grin open the fibers, you will see that the base of the fibers are darker than at the tips. It is almost as if they have been “frosted” at the tips like highlights in hair.

Antique wash

Sometimes the chemical treatments are not meant to make a rug shine more brightly, but are meant to “age” the rug to make it appear to be older than it is. “Antique wash” is a more aggressive treatment to not just eat away at the wool cuticle layers, but also to help fade/mute the colors substantially. True antique rugs have a certain patina and mellowing of the colors that comes from age and use. In an attempt to try to attain that same result in a new rug, there is aggressive degradation of the rug that can lead to an almost disappearing of the colors as well as wearing down of the fibers. As with hair that has been too aggressively treated with bleaches or peroxides, the strand can break, become more brittle and can lose the ability to hold color. Wool is no different.

Poorly executed chemical processing can make a rug’s original colors disappear. It can also create a rough and brittle texture to the rug. In some new rugs where this chemical antique wash work has been too aggressive, the rugs are sometimes dipped in ink to try to create something decorative from a rug that has essentially been burned of its wool content.

How to identify antique washed rugs

Wool rugs that have been given an “antique wash” will have a strong color change from the back of the rug to the front. In some contemporary rugs with this processing, both sides are processed, so grin the rug fibers open to see the original color in the middle of the fibers. If that original color is very strong, then you will know this rug has been chemically treated.

Tea wash

Other rugs today are “mellowed” by covering them up in an over-dyeing process referred to as “tea wash” or “herbal wash” treatments. In some countries, rugs are packed in tea leaves to help give this type of gold/brown hue naturally to help soften the rug’s colors. In most cases today, the rug is “tea washed” using solutions that can range from natural dyestuffs to chemical solutions such as potassium permanganate. The quality of this chemical treatment varies as much as with the other treatments. You have low-end applications, which are essentially sprayed on one side of the rug only, and higher-end applications that have the rug dipped in the solution to try to attain an even result.

How to identify tea washed rugs

Wool rugs that have been “tea washed” have an overall gold or brown tone to them. The fringes will be beige instead of white, and this can wash away with fringe cleaning solutions, so be careful. If you grin open the rug fibers, they will be darker at the tips instead of lighter.

Check back next week as we wrap up this series on chemically sensitive rugs, where we will discuss the dangers from chemically washed rugs.