Hats should not be washed or dry cleaned. Unless stated otherwise, hats are not water-resistant. This means that drizzle or light rain will not damage your hat. A hat cannot replace an umbrella, however.
A dusty hat can be cleaned gently using a horsehair brush and its shape can be ‘refreshed’ in mild steam (over a steam iron or a kettle with boiling water, at a minimum distance of 30 cm). If your hat loses its shape, you can reshape it by steaming, forming it into its original shape and leaving it to dry.
Small local grease stains can be cleaned with a wet cloth – wipe the stained area only, shape the hat into its original form and leave it to dry.
The best storage method is using a dummy head or by placing it brim up. This is especially important for hats with a large brim. Hats should be protected from dust, preferably in a box or a closet.
Sewn products should not be washed either, as the material can shrink and the product can lose its shape. Stains can be cleaned using a moist cloth or sponge with common solvents and a small amount of water.
Knitted products should not be washed, only cleaned e.g. using tetrachlorethylene (‘perchlor’) or best entrusted to a dry-cleaner.