Have you guys heard of soap nuts? They are actually the berries of the sapindus tree and contain naturally occuring saponin- basically soap that has many uses, including as laundry detergent.
I recently bought a sample from NaturOli for $1.95, plus $1.84 shipping on Amazon. To wash, you toss the linen sack with a five or so nuts into your wash and let the washer do its thang. You can reuse the nuts several times, so my sample pack is good for about 5 washes.
I chose NaturOli because they got the most positive reviews on Amazon. Most of them noted fabrics that were soft and required no softeners in the washing/drying process. My experience with these nuts is a little different. My clothes came out clean, with no scent (NaturOli notes you can add a few drops of your essential oil of choice to scent laundry), however the softness of my fabric did not seem to change. I may have not noticed anything due to the fact that I already use "environmentally friendly" laundry detergent, made by CostCo. It is basically the store brand of Seventh Generation detergent, also available at my CostCo.
Would I continue to use soap nuts? I think soap nuts are a great alternative to many common detergents that contain harsh chemicals. However, even if bought in bulk, the price of soap nuts does not compete with the price of my CostCo detergent. As of right now, I'll be sticking with the liquid detergent.
I do know the Kirkland Signature brand contains sodium lauryl sulfate, so that may sway me as I learn more about the ingredient in the future. This is my understanding right now: SLS is a skin irritant, but is not a carcinogen. Unfortunately, carcinogens are associated with SLS due to its production process- if done wrong, the carcinogens are produced and included with SLS in the products. I would love to hear any information you guys have regarding this issue. Thanks!