If your cloche is crushed or fedora flattened, there's a few home remedies to try before retiring your felt hat. The process, which involves steaming or stuffing the hat, an be approached several ways to accommodate the extent of damage and the coarseness of the fabric. However, repairs to felt hats should never involve an iron, which can singe the material.
Gently pop out any dents.
Stuff the entire hat with tissue paper.
Check the progress after a day, though it could take several days depending on the hat's style and the coarseness of the fabric. Remove the paper when the hat regains its shape.
Set a full tea kettle over a gas or electric range. Maintain the steam so it escapes the spout steadily but not forcefully.
Position the warped area over the steam for up to 30 seconds or until the fabric is evenly saturated.
Reshape the area with your fingers without overworking the fabric. Allow it to cool and stiffen.
Submerge your hat in clean lukewarm water.
Shake off or wring out the excess water.
Let the hat dry on your head until it regains its shape. Use your fingers to smooth out any wrinkles.
If your hat is warped beyond reuse, the fabric can be used to make a hair accessory or to insulate rubber boots.
Never use an iron to reshape a felt hat. (ref. 2)