While it is necessary to wash your hat, you must do it with great care. Taking such hats to the dry cleaners is not a good idea. The hat could be able to handle a washing machine depending on the materials it's made of.
If it's made entirely of cotton, it'll last a long time and can be machine washed. However, it is not recommended that you use a hat dry cleaning service when washing your hats. It is because it may apply to problems like structures being different and shrinking. The fabric may fade soon.
You should avoid taking your hats to the hats dry cleaning service. Instead, it is recommended to lay out or hang the lid if you want to take comprehensive care of it. There will be a major problem if you dry cleaned the hat because it would alter the stiffness of the hat. It can also help if you spread it out in the sun after washing the headwear. It is great at removing stains and eliminating odors.
Original Source: https://www.quora.com/Should-you-dry-clean-hats-Why-or-why-not/answer/Hello-Laundry
