After using Eco Laundry Balls for nearly three years I can say 'hand on heart' that they do work. But, I will make a few exceptions. I am extremely happy with them, and love the fact that the water leaving my washing machine is non-polluting. I even use it to water the vegetable garden without worries or concerns.
The way Eco Wash Balls work is to harness the power of water to do all the cleaning you need. By allowing the water to ionise and basically become more energetic it dislodges dirt from your laundry. But (there is always a but), without harsh chemical detergents the power of this laundry cleaner is not the same as some of the old chemical based originals. If you want to throw your laundry into the machine without ever having to check for greasy stains or ground in dirt you really have no option but to stick with the likes of Tide and Vanish. But, if you are happy to spend just a few minutes checking over the laundry and then simply soaking heavily soiled items overnight in a little soap water, or adding a sprinkle of baking soda to tough loads of laundry, Eco Laundry Balls could be for you.
I believe those few extra moments doing the laundry are hardly a hardship. And, because those Eco Wash Balls are saving me money and making my home less polluting I am perfectly happy to carry on using them, even if I do very occasionally need to help them out. So yes, Eco Laundry Balls do work. In fact they work very well, but they are not miracle workers because they are not loaded with harmful detergents!