A soft wash incorporates special low-pressure nozzles on the end of a pressure washing gun or wand. That's combined with a biodegradable chemical that removes the biological elements (mold, algae, pollen, dirt, moss) and other stains without damaging surfaces on your home or killing your plants. As far as rust removal, we use a special chemical mix that is sprayed on and within seconds it disappears without harming the surface it is applied to.