Sorry but that is nonsense. There is not even nearly enough energy in a laptop battery to empty a bucket of water. There is not even enough heat to warm the water a significant amount, which is why it can not even get to the point of a runaway reaction to begin with. The internal short just dissipates the energy slowly, without any spectacular event. Regardless of salt content, but salt would indeed help discharge the battery even without a fault.
And of course there are other ways to handle a battery (regardless of it’s health) safely.