She made two of these filtration containers, with the order of the filter layers completely reversed in the second one.
She placed the twice-filtered seawater by the fire to heat it. As the water evaporated, white salt crystals and some yellow particles slowly formed on the walls of the bamboo tube.
She carefully scraped off the yellow parts and threw them away. The white salt crystals were scraped directly into the remaining seawater, which was then boiled down until it reached the consistency of rice porridge.
By the time she had filtered and then evaporated all the seawater from seven or eight bamboo tubes, more than an hour had passed.
She went back to the creek for two more tubes of fresh water, filtered it once, then stirred in the saltwater porridge, letting the salt dissolve as much as possible before heating it again.
After repeating the filtering and evaporation process several times, she finally obtained a small handful of relatively clean, white sea salt crystals.
