Idea from Allergies Web Site
To make an isotonic solution (one similar to the salt content of your bodily fluids), mix 1/4-teaspoon salt in an 8-ounce glass of warm water and add a pinch (1/4-tsp.) of baking soda. Discard any unused solution.
You may chose to use filtered or distilled water if your water contains a lot of chemicals. Table salt can be used, but many prefer to use non-iodized canning or pickling salt. Using baking soda improves the mucus-solvent properties of the solution.
ENT states: 8 oz distilled water, 1/2 teaspoon salt, mix well.
What John did for me:
1 teaspoon salt to a pint of distilled water. Mix well. We stored it in either a Tupperware container or a used 19 oz water bottle. Lasts 1-2 weeks.