From the top
Your Love Glove/Muffy is clean and immersed in the bucket. Squeeze Muffy while immersed in the suds, so she sucks up as much of the good water as possible. You start at the top of the car, commonly known as the roof, going from panel to panel working your way down. (Or from the bigger flat bonnet and boot panels on a car like the Shelby Cobra here) At the completion of washing each panel, you rinse, and while you’re at it, to deter water drying on the car, you keep the rest of the car wet too. The reason you start at the top is to minimise contamination of the bucket. The lower the panel is on the car, the more it collects road grime. The more road grime you get in the bucket, the more hazardous it becomes to wash with.