Never use hot water, which is roughly above 90℉ or 32℃. Hot water will shrink the wool fibers. Set the hat into the bowl or basin before you add water to make sure it will fit in the container once the water is added.
If you can’t find a wool-specific detergent, make sure you use a mild detergent. Baby detergent, such as Dreft, or detergent for sensitive skin, like All Free Clear, are good alternatives.
For stubborn stains, use a soft toothbrush to lightly scrub the hat. The fibers are damaged easily, so never scrub wool with a harsh brush or with hard strokes. Be sure not to stretch the hat out while you wash it, as it may not return to the proper shape.
After it soaks for a while, give it a quick massage again to remove anything that was loosened while the hat soaked.
Be sure to only wash your hat with similar colors or add a color catcher cloth to make sure your hat does not soak up any other colors. If your washer does not have a center agitator, it’s okay to wash the hat by itself. Only wash stocking cap style hats in the washer. Hats with a bill, brim, or other structural pieces should only be washed by hand.
Never pour the detergent directly onto the wool hat, as too much detergent on the hat could damage the fibers. Either put the detergent in after water has been added or pour it away from the wool hat.
Water temperature on the warm setting should be 80℉ (27℃) or below. If you don’t know the temperature of the warm setting, it’s best to stick with cold water.
If the washer you want to use does not offer a gentle setting, it is best to wash your wool hat by hand.
Place a fan near the hat to keep air flowing on. This will help the hat dry faster without the damaging effects of a dryer.
Also, try hanging the hat from a hanger on a doorknob.
Another option is to place the hat on an upside down bowl, a coffee canister, or something else that is round to help the hat retain its shape.
This mainly applies to floppy sock hats because baseball hats or other wool hats with structure to them will stay in shape.
