How to Wash Out a Flask

Clean out the flask with hot, soapy water.

Thermos flasks are practical and money-saving items to take on trips, and they soon pay for themselves through fewer visits to expensive coffee houses. Flasks can keep drinks hot for roughly four hours, or cool drinks cold for up to 12 hours. The mouth of a traditional thermos flask is small, making it difficult to clean the inside after use. However, cleaning can be carried out with the use of a baby bottle cleaning brush.

Things You'll Need

• Soapy hot water
• Baby bottle cleaning brush
• White vinegar
• Baking soda

Instructions

1. Pour out any remaining contents from the flask. Mix hot, soapy water and pour it into the flask until full. Push a baby bottle cleaning brush into the flask, turning it several times when inside to clean the interior walls. The brushes are long and thin and made of plastic, which won't harm the flask.

2. Remove the cleaning brush and pour out the soapy water. Rinse out the flask several times with hot water to remove all soapy residue. If the interior of the flask still smells from drinks it held, pour white vinegar into the flask, and then some baking soda. The baking soda will react with the vinegar and foam. This reaction will help clean the flask and also get rid of the smell. Leave the solution in the flask for 10 minutes before pouring it out and rinsing the flask several times with hot water.

3. Turn the flask upside down and leave it to dry. When the interior is dry, store the flask without the top on to help prevent odors or bacteria from building inside the flask.

References

• Cleaning Tips: Cleaning a Thermos Flask