We’ve been exterior cleaning in NJ for some time now. While many of our clients own their own machine they still trend towards hiring a professional. The secret is no secret. We’ve been using our own special blend of detergents with the main ingredient chlorine. It does wonders on vinyl siding and removing green mold. It’s a must when it comes to whitening white aluminum wrappings and white painted structures. It’s not about the pressure which most times leads to damage. We use a soft-washing techniques and rarely use pressures over 400 psi. It can be frustrating learning whats nozzles draw soap and which ones to use for pressure to the right application. Some soap nozzles do not work on all machines. They must be matched to the proper orifice size of the nozzle to the proper gallons per minute of the machine.