Distillation is the best way to remove chloride ions from water. Unlike filters which allow some of the tiny ions to get through, distillation heats water until it evaporates into steam, leaving the heavier contaminants, including chloride, behind.
The steam is then collected in a condensing chamber where it is cooled until it becomes liquid again. This condensed, distilled water is very pure, though it is somewhat undesirable for drinking because the lack of minerals makes it taste flat.
Bore or drill a 1/4-inch hole through the center of two rubber stoppers. Insert the ends of a 12-inch length of 1/4-inch rubber or plastic tubing into each stopper.
Place one of the rubber stoppers in the bottle to seal it. Place the sealed bottle in the bowl of ice water.
Fill a test tube halfway full of water containing chloride ions. Place the other rubber stopper firmly in the test tube to seal it.
Hold the test tube over an alcohol or Bunsen burner with a test tube holder. When the water begins to boil, steam will flow through the tube and condense in the bottle. This condensed, distilled water will be free of chloride ions.
Household distilled water systems are available commercially to remove chloride ions and other contaminants from water on a larger scale.