Our recommended “best before” date is one year for kiurushi as it is a raw material. Mixed urushi like eurushi, kuroroiro, and kuro urushi, can be used so long as it has not hardened. We recommend proper storage of all urushi to extend its lifespan for as long as possible, as it is a precious natural resource.
After each use, screw the cap tightly and store urushi in a cool, dry, and dark place to ensure its longevity. In hotter or more humid months, we suggest wrapping urushi tubes in newspaper or placing in a plastic bag, and storing in the refrigerator, while ensuring there is no direct contact with other objects.