Exterior cleaner

Does anyone know a good pre soaking soap that will take most the grime off before I mitt wash. Winter is about over and I want to try and get most the stuff off before I even bring a mitt to the car, almost looking for something that lowers the surface tension like a degreaser prior to washing.

Does anyone know a good pre soaking soap that will take most the grime off before I mitt wash. Winter is about over and I want to try and get most the stuff off before I even bring a mitt to the car, almost looking for something that lowers the surface tension like a degreaser prior to washing.