Though this article is in reference to animal fibers, such as wool, it's principles also apply equally well to plant natural fibers such as cotton and linen.

Natural fibers like wool are not meant to be washed often, if at all. The fibers themselves are rarely penetrated by dirt and most often dirt can be shaken off and the garments freshened by hanging in a ventilated area, preferably outdoors. However sometimes washing becomes necessary, due to spills and dried on liquids that will not shake off.

Felting and changes to the makeup of the fibers is significantly exaggerated by heat and water. If you have to wash the garment, it is essential that it be done carefully. Wash in cool or warm water. In addition, any kind of mechanical agitation will increase the adverse effects of washing these natural fibers. Always wash by hand, never in a machine, unless the yarn is specifically labeled as “machine washable”. Even then, we suggest knitting a sample swatch and testing it in your machine, before committing the entire project. Though the fiber may be machine washable, the dyes could run, leaving a mess on your finished knit.

There are several commercial products available, advertised as safe for natural fibers. We will not review these products, as we are focusing this article on the most natural ways to wash these fibers. Be aware that many of these commercial products contain ingredients like these, which should be avoided:

Methylisothiazolinone - A powerful synthetic biocide and cytotoxin which is used in numerous personal care products

Benzisothiazolinone - another powerful biocide that is known to be a toxic material for the human immune system, and is also classified as an irritant for the skin, eyes and lungs

DEA (diethanolamine), MEA (monoethanolamine) & TEA (triethanolamine) - These are hormone disrupting chemicals that are are readily absorbed in the skin

When washing anything, there are two basic options; Soaps or Detergents.

Soap is a salt of a fatty acid, either animal or plant based. They are made by reacting the fat with either potassium hydroxide, sodium hydroxide or both. Because they are made using potassium or sodium hydroxide the resultant product is always going to be very alkaline. Typically around pH 9.

Detergents use several different chemical compounds to build on the basic concepts of soap. They add surfactants, whiteners, softeners and many other attributes to the product. However, typical detergents are also around pH 9.

The problem with either of these products in general is that natural fibers like wool, or even the hair on your head, react badly to high pH levels. The alkaline nature of these products raises the surface of the fibers which leads to their felting and loosing their dimensional stability. This is why washing your hair with dish soap or laundry detergent would result in tangled, unmanageable hair. The hair on your head isn't a whole lot different than the hair on the animal the fiber is made from.

Acids, on the other hand, cause the fibers to lay flat and become smooth. This is part of the reason why an acid based conditioner causes hair to become untangled and manageable after being washed by an alkaline soap or shampoo. This is why something as simple as white vinegar can make an effective conditioner.

While you can reverse the effects of a high alkaline soap or detergent on fibers by rinsing them in an acidic rinse, it doesn't completely reverse the process. When the fibers are raised in the alkaline wash, even with very light agitation, some of them will be broken and tangled together. The acid rinse cannot fully restore what was broken off and felted during the wash.

Many natural do-it-yourself articles recommend just this; “wash in a pure natural soap and then rinse in water with white vinegar added.” Although this has been done for years and many people swear by this method, we cannot recommend it, because in the long run it will accelerate the wear of the garment.

A better approach is to wash at a neutral pH from the start, to avoid the alkaline wash and the need for some sort of acid rinse afterwards, though a light vinegar rinse after washing won't hurt. We have found two ways to get to this in the most natural way possible:

The first is baby shampoo. One of the reasons that baby shampoo doesn't irritate eyes is that its pH is balanced at around 7. Ideal for washing natural fibers. While regular commercial baby shampoos are not the best choice due to some of the chemicals added, they are probably better than the commercial fiber washing products. However, there are now several options in natural baby shampoos that make this a really good option for washing your natural fabrics. Even the major manufacturers of baby shampoos are offering “natural” versions of their baby shampoo products.

The second option is a product produced by Dr. Bronner's, a well known natural producer of organic and natural soap and care products. The product is a mild detergent named Sal Suds. Sal Suds has earned an A rating from the Environmental Working Group, an organization that rates the chemicals in products for safety. While Sal Suds is classified as a detergent and would normally be at a pH near 9, Dr. Bronner's has neutralized the excessive pH with citric acid to make the final product virtually neutral in pH at around 7.

Either of these will make an excellent, non-toxic way to clean your natural fiber knits.

To summarize:

1. Natural fibers like wool must be washed by hand in cold water, or it will felt and shrink.
2. Gently agitate the knitted item in the water.
3. Never wring out or scrub the item.
4. When washing drain and rinse until the water flows clear.
5. Always support the item as you transfer it to a dry towel.
6. Lay the item flat on a dry, absorbent towel and roll up in the towel. Do not wring the towel.
7. Place the garment on a dry towel and reshape into its original shape.
8. Allow to completely dry before moving.
9. Once dry, store flat, never hang a knitted garment.