"The secret to pressure-washing is to use the gentlest possible pressure," says painter Mauro Henrique, a TOH TV veteran. Start with the lowest- pressure setting and either the green or yellow spray tip to minimize any surface damage. You can always ratchet up the pressure if necessary. Also, skip harsh bleach in favor ‚Ä®of a green product to protect any surrounding plants. Try D/2 Biological Solution mixed with an equal amount of water. With siding and roofing, never spray up at the bottom edge of a course; the water can dislodge shingles or get into the structure of the house.