Now lets talk about actually washing a trailer. Always apply soap with your soap nozzle, low pressure from soap container, from bottom to top, other wise the soap runs down and streaks. next use the soft brush to scrub the dirt. Now switch to you high pressure 60 degree nozzle and rinse from top down. if you want to, now is the time to put some liquid wax mixed with water, about 4 or 5 ounces to a gallon into a separate jug an again apply using the low pressure nozzle and rinse again with the high pressure. Side note. always test first for color change. Filion type siding and some cheaper Gel coats will absorb the soap colors. Never use a red or brown colored soap. Always use the lightest colored soap you can. ONE MORE NOTE. RUN as fast and as far as you can from an AIRSTREAM Alumiumn trailer. Any caustic cleaner will remove the shine.