Things You'll Need
Wash your hands with soap and warm water to clean them. Use a towel to dry them off.
Clean the pot, pan and their lids with warm water and dish washing soap. Use a pot large enough so your glass bottle can fit in it. Use a pan that can easily hold 1 quart of liquid.
Sterilize the glass bottle and its lid. Fill the pot with tap water and place it on your stove. Unscrew the lid from your glass bottle and submerge both the bottle and lid into the pot with water. Cover the pot with its lid. Bring the water to a boil and wait for 15 minutes before turning off the stove. Leave the glass bottle and its lid in the pan as the water cools off.
Place 4 cups of distilled water into the pan. Avoid using tap water because it can contain bacterial impurities. You can find distilled water, which is used for steam irons, in the laundry supply aisle or bottled water aisle of supermarkets.
Add 2 tsp. cooking salt to the pan with water. Cover the pan with its lid and place it on your stove. Boil the liquid for 15 minutes.
Turn off the stove and allow the liquid to cool down to room temperature. Keep the lid on the pan to protect sterility.
Take the glass jar and its lid out of the pot with water. Avoid touching the inside of the lid and jar.
Pour the saline solution into the jar and seal it with its lid. Label the jar with the date and time you made the solution. Leave enough space on the label to add the date and time that you open the bottle for the first time and the date and time to discard the solution. Throw away any solution 48 hours after the first time of opening the jar. Discard solution from unopened jars after one month. Wash the jar and re-use it.