Or a way to replace the water
I'm sure the water is boiled via the fire then cooled with new water to a comfortable temp. Atleast it looks like the fire is only smoldering maybe enough to maintain temp. I'm sure the boiling kills anything leftover from the previous soaking.
You would need a BIG fire to get that all water to boil.
Besides that, oil, dead skin and other stuff doesn't get removed just by boiling.
Or a way to replace the water
I'm sure the water is boiled via the fire then cooled with new water to a comfortable temp. Atleast it looks like the fire is only smoldering maybe enough to maintain temp. I'm sure the boiling kills anything leftover from the previous soaking.
You would need a BIG fire to get that all water to boil.
Besides that, oil, dead skin and other stuff doesn't get removed just by boiling.