It is the method to loosen the hardened cotton and make it elastic again. In particular, futons filled with cotton can easily keep moisture in and tend to become hard after a long period of use. Also, umo-butons become clumpy or uneven because feathers inside tend to become entangled. When such problems occur, you can use Uchi-naoshi service which can make your futons return to the elastic and soft state like the brand-new ones. The desirable timing for uchi-naoshi service would be after use of a kake-buton for 5 years and a shiki-buton for 3 years. When you use the uchi-naoshi service, you can replace the futon’s outer and lining fabrics with new ones and turn the futon for adults into the one for kids or turn it into zabutons.