I have an idea about a cleaning agent, bleach.... it is commonly used for household cleaning including vinyl siding. I am wondering if you can take a large container, say 55 gallon drum and fill it with water then add 1 chlorine tablet that is used for swimming pools to make a drum of siding cleaner. Plz text back or call 479-280-9395 I rarely get on here but also my email is colt@pressurizedpowerwashing.com