Using the best solvent might help make a concentrated solution.
If you empty the remainder, that takes away the old concentrated solution.
This assumption will be valid for all but very concentrated solutions.
What is left is a more concentrated solution of salt water.
After drying, one or two coats of a more concentrated solution are usually applied.
The pH value of a concentrated solution will lie between 5 and 6.
But it was a reasonable hope that in such a concentrated solution some int resting reactions would take place.
Concentrated aqueous solutions are red at room temperature but become blue when heated.
The resulting ash is then redissolved into concentrated solution in hot water.
This technique requires the use of relatively concentrated solutions.