Thank you for posting this, artemis. I really enjoyed watching it. I've been to a few historic sites where they do that kind of demonstration, but have never had the pleasure of being there at the right time to see the laundry demo. So I am really glad to have the chance to see this.
I wish I had thought of a battle board when I used to wash our laundry in a huge bucket on the camp grill when my kids were young. The place we camped every year had a large round concrete campfire with a steel grill that I used to set a huge aluminum pail (about the size of a half barrel) to boil water to wash the clothes. I'd stir them with a stick and wring them out by hand. That battle board would have been so useful!