The stains can be removed with a humidified natural sponge, and soft soap.
When the hat is not being used don't place on its brim instead, place it on the crown because it can be deformed.
Don't leave de hat inside of a vehicle where it can reach sunlight because if the hat is made of straw, it gets dried and broken, an it the hat is made of other materials gets deformed and becomes color less.
Carefully manipulate the hat by its crown.
If the hat gets wet, let it dry with the environment temperature always taking care it conserves its original shape.