One ounce of household bleach (e.g. Clorox Regular or Clorox Ultra) can be added to one liter of water. After mixing for 10 seconds, pour into a water bag and place overnight.
Finally rinse thoroughly and dry naturally.
Use hot soapy water to rinse the water bag whole body. If the effect is not good, use 1/4 dry soda and 3/4 water mix solution, shake for 30 seconds, add a cup of lemon juice, shake for 10 seconds, loosen the lid, discharge the gas. Repeat this three times so that the gas is discharged as much as possible and soak for 20 minutes and rinse three times with hot water.
Warning: When adding lemon juice to dry soda, bubbling and negative pressure will occur.