Spot Free Rinse

Thank you for any and all help. I sincerely appreciate it.

I am wondering what system, or additive is used at self serve car washes to create a spotless finish (spot free rinse).

Is there a generic procedure? Or, do people have different twists, turns, and techniques?

Again, thank you very much for your help.

sinc, --g.

Usually spot free rinse is created using reverse osmosis. Mine is made by a company caller 'pur clean'. Google it and learn what it is and does.