To Bleach or Not To Bleach?

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During several recent rug seminars, the topic of bleach has become of interest. Should a rug cleaning specialist use bleach? Let’s take a look at this controversial subject.

The WoolSafe Organization has been referenced several times over the years in my columns with regards to their guidelines for testing cleaning products as safe to use on wool. WoolSafe wants products to be free of reducing and oxidizing agents, as they can remove color and, at high concentrations, damage the fiber. However, they do make exceptions for stain removal products allowing peroxide-based oxidizers. It must be noted the organization’s main focus is testing cleaning products for wall-to-wall wool carpet, not oriental rugs.

Most hand-knotted rugs are exposed to chlorine bleach in a finishing process before reaching a retail store with names like luster or antique wash, a topic that was discussed in my March 1998 column. To produce rug sheen (Image 1), it is quickly washed with a 1-2% solution of chlorine bleach. A stronger solution can be used to remove color for an “antique” look (Image 2). The oxidizer is then neutralized with an “antichlor” (typically acetic acid or a reducer like sodium hydrosulfite) and the rug thoroughly rinsed. These are very controlled reactive processes.

Both processes remove the cuticle or scales found on the exterior of the wool fiber (Image 3) and excess dye. The practice is an old one documented in magazines going back to 1906. The Rug Renovating Company now in New Jersey has done such treatments since the 1930s, which you can read more of in the ICS April 2007 issue.

Only a company who understands this complex process – and not the average rug cleaner – should do a luster or antique wash. Does it shorten the life of a rug? Yes, but those American Sarouks given an antique chlorine wash in the 1930s are still around.

We have discussed the use of oxidizing and reducing agents before for removal of fugitive dye bleed and certain stains. This requires training, skill and patience to effectively remove an unwanted dye and not damage a rug (Image 4).

So what is all the controversy about today? Several rug wash companies are adding very small amounts of chlorine bleach in the form of Di-Chlor to their immersion wash process (Image 5). Wool will dissolve with 6% household laundry bleach or 60,000 parts per million (ppm). The wash process that is done by some companies uses only 10 ppm of this material. A poison is determined by the dose – small amounts of bleach can remove certain stains and dye bleed without long or short-term damage to the rug.

Some argue any amount of bleach is detrimental to wool. As discussed above, most rugs have been exposed to bleach in the finishing process, including the well-known machine-made brand Karastan®. In fact, municipal water supplies have about 4 ppm of sodium hypochlorite (bleach) added to water for sanitation. So virtually all rugs have been exposed to bleach at one point in their life.

If you are cleaning rugs using the water extraction process, I am not advocating you start adding bleach to your rinse water. But do be aware certain rug plants that have immersion equipment and proper training might use this process to remove organic materials, dye bleed and certain stains. At 10 ppm, it is lower that the amount of oxidizers used to give the rug luster in the finishing process.   


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