The laundry balls are calibrated magnetically, specially to alter the basic nature of water and increase its natural solvency. When water, or any stream of atoms, enters a powerful magnetic field, it physically changes in the same way atoms change when run through particle accelerators used by physicists. In effect, the water is ionized. Negatively changed oxygen ions are stripped from stable water molecules and are freed to perform a number of tasks. Among other things, the altered water can dissolve scum lines, help stabilize pH, kill algae and microorganisms, and release stains and odors from fabrics.
Water is a uniquely polar molecule, like a little magnet.
Its polar nature allows it to dissolve almost anything. And being such a good solvent you would expect that water alone could make a good cleaning agent. And you would be right. The only problem is that water sticks together. When you think of water you think of two hydrogen and one oxygen molecule.