There are several effective methods to clean a hat, depending on the hat type and level of dirtiness. The most recommended way is to hand wash it gently with mild detergent or soap, which helps preserve the hat’s shape and color over time. Here is a general guide:

1. Remove superficial dust and lint using a hat brush or cloth.
2. Fill a basin or sink with cool or warm water and add a mild detergent.
3. Spot-clean problem areas using a soft brush or toothbrush dipped in the soapy water.
4. Soak the entire hat in the soapy water for 10–30 minutes.
5. Gently scrub the sweatband and stained areas as needed.
6. Rinse the hat thoroughly with clean, cool water.
7. Pat the hat dry with a towel without wringing it.
8. Air-dry the hat away from direct sunlight or heat, placing it on a round object to maintain its shape, such as a melon, coffee tin, or balled-up towel.

Additional tips:

• For wool hats, only apply cleaner to dirty spots.
• Avoid harsh chemicals, bleach, ironing, or intense heat which can damage or discolor the hat.
• Use baby wipes or a lint roller for quick spot cleaning.
• To remove sweat stains, soak in a vinegar-water solution or use a baking soda paste.
• Frequency of cleaning depends on use, but weekly for daily wear or monthly if worn less often is suggested.

Machine washing is generally not recommended unless using a hat cage and gentle cycle. Dishwasher washing is possible but hand washing remains the safest option. Specialized hat-cleaning machines exist for collectors or heavy users. This approach will keep hats clean and well-maintained without risking damage or deformation.