That's not washing clothes. That's rinsing clothes. To wash with water only, the old times folks would bring water to a boil in a cauldron, throw the clothes in, and stir them with a wooden club. A washing board could be used as well, with less than boiling water. Of course if they had soap, they might skip the boiling water, would use merely hot water, the soap, and a washing board. That being said, obviously I've never seen such ancient practices in real life. However, if you have ever washed anything by hand, like microfiber clothes for lenses, or whatever, you'd know the process with a modern detergent. Not that different from the more primitive soap. Though few of us would have washing boards.