Like most new products, you want to make sure it is clean before use. You will also should clean the growler every time you empty it.
This product IS NOT dishwasher safe and can get ruined if you try to clean it using the dishwasher. Dish soap is also not recommend for cleaning.
It is best to fill the keg with warm water and a cleaning tablet, then shake well and rinse. Even better, if you have any CO2 left, you can quickly pressurize the cleaning solution and run it through the tap.
If you don’t have any cleaning tablets, you can substitute baking soda.