In my country we used to use woolen matresses, which would be completely emptied and washed twice a year, and the wool would be dried in the sun for a good two

In my country we used to use woolen matresses, which would be completely emptied and washed twice a year, and the wool would be dried in the sun for a good two days, then whipped with a long stick for couple hours, and then filled back in the washed cover again. Nowadays it's very rare unfortunately.