The Neutralizing Pre-Wash is used for initial SoClean setup. It is important to use the Neutralizing Pre-Wash to hand-wash your PAP equipment before you connect your SoClean for the first time. The Pre-Wash is a fragrance-free, dye-free soap that neutralizes any odors and scents on your PAP equipment.
You can see detailed instructions for use here. (scroll down for English)