The best way to clean a tatami mat is to take it outside, shake off accumulated dust, leave the mat in a dry location for several days, wipe it with a dust cloth, and attack stains with diluted white vinegar. This three-day process requires a large bowl, clean water, white vinegar, a microfiber cloth and a large sponge.
- Take the mat outside
Take the tatami mat outside, and shake it vigorously. Leave it in a safe, dry location for at least two days. This gives the mat time to dry out and reduces the chance of mold development.
- Dust the mat with a cloth
Dust both sides of the mat with a dry microfiber cloth. Cotton cloths also work, but microfiber is the best choice because it removes tiny dust particles trapped in tightly-woven straw tatami mats.
- Wipe stains with diluted white vinegar
Combine equal parts clean water and vinegar in a large bowl. Saturate a large sponge in the diluted vinegar, wring it out, and scrub discolored sections of your tatami mat. Apply more vinegar as needed.
- Dry the mat
Dry the mat with the microfiber cloth. Keep it outside until the straw is completely dry, and then return it to its customary location.