Straw can be tricky to clean, but a lightly damp cloth will help remove dust and light marks and stains. Go very light on the moisture as you don't want it to become so wet that you start to misshape the straw. You can also clean your hat using a soft-bristled brush which will remove dirt and debris, including pollen and dust. Brushing your hat regularly after use, should prevent dirt build-up and discoloration.
Avoid The Rain
Straw hats are meant to protect you from the sun, but not from the rain. If your hat does get wet, it is going to lose its shape permanently. Be careful in the ocean, by the pool and do not wear it in a thunderstorm. Straw will lose its density and finish once it's soaked or experiences any kind of heavy moisture. While a quick steam is healthy and good for straw, getting it sopping wet is not.
Handle With Care
If you have noticed your hat gradually losing its shape when wearing frequently, this may be a result of how you hold it. When holding your hat, do so only by the wings. If you grab it from the front or pinch the crown, this could cause the straw to break over time.
The fibres in your straw hat are vulnerable to extreme temperatures, so make sure not to leave it in hot places like your car. Extreme heat will crack and dry out the fibres. Store your hat in a place where it's cool, for example, on the top shelf of a dark, dry closet. Never put your hat in a plastic bag, being a natural fibre, this could lead to discoloration and mildew.
When storing you hat for a long while it can become dry and brittle. If it dries out completely, it can easily crack or split. Use a steamer, a quick thirty seconds of steam all over the straw will be all you need. If you don’t have a steamer, place it on your bathroom and run a hot shower to let the steam fill the room. It won’t need long.