I built a washing trough
Since I don't have a hot tub, I bought five 8-foot 2x4's and built a frame that is 16' by 4'. I place it on a relatively level spot on the edge of my driveway and lay a piece of plastic sheeting into it.I fill with water and add a few squirts of Joy dish-washing liquid. I lay out the flaked sail along the trough and unfold a section at a time and put it into the water. I scrub gently with a long-handled soft brush and then pull the clean section out onto the lawn.I flip the sail over and repeat on the other side. Then I drag the sail onto the lawn, spread it out and rinse with a hose on both sides. Let dry and then fold.