Mattresses and pillows quietly collect sweat, skin cells, and odours over time. You might change sheets regularly, but the bedding underneath still absorbs moisture. This can lead to that slightly stale smell in bedrooms.
Putting mattresses and pillows in sunlight—on a balcony, near a sunny window, or even just propping them up so air moves around—helps dry out trapped moisture. Sunlight also has a mild disinfecting effect and can freshen fabrics naturally.
You don’t have to do it daily. Even once in a while, a few hours of air and light can make beds feel crisper and less musty, especially in humid seasons.
