David Sweeney brought up a critical piece of the 'stripping & color run removal' picture. How dyes react to reducers and oxidizers varies from one dye type, or formulation, to another. Acid dyes react quickly to strippers but since their formulations are generally blends of primary colors, each of which can react at a different rate to a reducer, they often 'change' color as they are stripped. Natural dyes don't generally 'strip', though some brighten with the application of a stripper. If anyone thinks natural dyes don't run, think again. Dye bleed in natural dye rugs is common; it usually happens in production washes, but can also occur during regular cleaning as well. Most natural dye color run can not be treated with reducers. To learn to strip rugs on a daily basis the first thing to do is to start working on your rug id skills, then start reading about dyes and how they work.
There has been a lot said about how stripper (sodium hydrosulfite) damages or 'yellows' wool. A popular authority in the rug washing field regularly states that strippers should be avoided because they 'damage wool'. This may be true in inappropriately high concentrations or faulty applications, but is not so when the chemicals are used correctly. It is common practice when dying wool with acid dyes to 'correct' your mistakes by boiling skeins of wool that came out the 'wrong' color in a bath of stripper to remove all dye from the fiber so it can be dyed again in a different shade.
Speaking of boiling wool yarns its worth noting that nearly every piece of yarn in every wool or silk rug we wash has been boiled or simmered in a water bath while it was being dyed. Most rugs we clean have been treated with powerful solutions of oxidizers, reducers, and acids during the production washes that nearly every manufacturer uses to make their rugs look like what consumers want to buy.
I am not suggesting that cleaners can be careless or use inappropriate chemicals and procedures. I do question blanket statements made regularly over the years by experts with agendas. Contentions that oxidizers can't be used on rugs, that warm water is dangerous, and a collection of other do and don't prohibitions, are not necessarily true. The rug producing industry has myriad procedures that run counter to the prevailing wisdom in the rug cleaning business. Rug producers don't like to talk about such things for fear of alarming the buying public, and they usually keep their procedures and formulations 'proprietary'. Learning more about how rugs are made and finished will help any rug cleaner understand the reactions that take place every day on the wash floor.
