Rinse your protein shaker after every use with luke-warm water.

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This is because if you use hot water, it may burn or bind the proteins to the bottle and make it difficult to remove. So even though you have washed the bottle, the residue that contributes to the smell may still remain.
Wash the protein shaker with dishwasher detergent.

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The detergent is more powerful.
Wash the protein shaker with white vinegar and water.
Don’t use too much vinegar or it will smell like vinegar. Aim for 50% water, 50% white vinegar. Let it soak for at least 45 mins.
Use citric acid from lemons when washing or rinsing your protein shaker.

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Alkaline solutions dissolve proteins and fats, acidic solutions minerals. Milk contains both, norm is to use acidic once a week.
Use baking soda with water when washing.

If you can, let the baking soda and water sit inside for an extended amount of time to help remove the smell.
What are some other things that you can consider to prevent your protein shaker from smelling?
- Consume your protein with water instead of milk and dairy.

- Wash it with water, then put it in the freezer till your next use. (The cold kills the bacteria that produces the smell)
Things that you should never do.
- Shake your protein shaker with boiling water. The steam could force the top off and send boiling water everywhere. Some guy burned half his face doing this a while ago
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