Liquids that produce a solid when boiled (polluted water, salt water, brine) produce more of that solid when they are heated above their boiling point. Similar to the known issue with the 1.5C temperature reset being applied multiple times when super-heated water boils, every tile that a liquid thermally interacts with while above it's boiling point will convert a percentage of it's mass to the expected solid. This allows the percentage conversion to occur up to 4 tiles.
E.g. brine which normally converts into 30% salt when super heated can produce up to 1 - (.7 ^ 4) = 75.99% salt.
Initial Conditions: 1kg of salt water, brine or polluted water at 500K, surrounded by 1 to 4 thermally interacting tiles
After 1 tick:
Heat polluted water, salt water, or brine above their boiling points.