DO NOT put your hat in the washing machine.
Things you'll need: Toothbrush and mild detergent (like dish soap).
How To: Mix a small amount of dish soap in a cup of water. Dip toothbrush in mixture and lightly scrub hat, in a circular motion, to remove dirt and small stains.
If a spot clean is not enough, use the same mixture and a towel to wipe down the entire hat. Rinse the hat quickly (avoid getting it sopping wet) and air dry.
Just like new! You'll be surprised at how well this simple method works. If you have further questions, don't hesitate to reach out at firstname.lastname@example.org.