What’s needed to clean a flask
- Bicarbonate of soda
To clean a flask and remove the stale smells
Bicarbonate of soda can also be used for removing lingering smells from your thermos. Put 3 teaspoons of bicarbonate of soda into your flask to clean it then fill it up with boiling water, then leave to soak for 1/2 an hour and rinse clean. This should remove all the odor.
How to Clean a Flask Stain
Bicarbonate of soda is excellent for removing stains from a flask thermos. The secret is to sprinkle the bicarbonate of soda in first (the amount depends on the stain) in the flask and then add boiling water and slosh around! The stain comes off instantly without any scrubbing the flask.