Wet
Dry it upside down, in shade, with paper in the crown.
Shake off standing water. Stand the hat upside down on its crown so the brim is not carrying the weight of wet felt, and loosely fill the crown with paper so it dries to the right shape rather than collapsing to a new one.
Give it 12 to 24 hours in a room with moving air. A structured hat wants a full 24 and a firm reshape by hand while the felt is still slightly damp.
Never a radiator, never a hairdryer, never a sunny windowsill. Heat drives the water out faster than the fibres can relax and sets the distortion permanently. That is the one mistake that cannot be undone.


