Mark,
Sodium Hydroxide is a very powerful and potent chemical that can be rather hazardous to use in heavier concentrations. It is the main ingredient in alot of deck strippers...........it kills plants and grass, and cannot come in contact with your skin.
Now, when people are using it for house washing, they are using rather weak concentrations of it..........so as not to damage yourself or your surroundings.
One of the easiest ways to add it to your cleaning mixture is to use what they call Ultra Clorox (wal mart also sells an Ultra version of their bleach). It contains a bit of Sodium Hydroxide. Also, there is a product called Clorox Outdoor. It is a concentrated bleach cleaner, comes in a one and a half gallon container, and can be found at Home Depot......maybe Lowes.
I would try the above products for starters. Sodium Hydroxide will give your house cleaning mixture some extra kick......perhaps reducing the difficulty of your cleaning, and therefore saving you time and money.
Just be careful not to use too much............and wet the flowers, etc down before and after you wash.
