From my trip to SJMK 팔만무도구 in Korea.
How to wash men:
- Soak in hot water for less than 1 hour. Over that, and the leather around mengane gets soft.
- Wash and scrub with dishsoap and a scrub until the water runs clean and the bubbles aren’t dirty.
- Dry with a fan in a dark area. Sunshine will damage the structure and leather (sunshine on wet leather is the real reason they tell you not to dry bogu in the sun).
- Apply dye with toothbrush if needed.
- Use camellia oil.
- Dip cotton into oil, place into shinai in two places:
- One right above the nakayui.
- One well below it, about midway between the nakayui and tsuba, right above the notch.
- Wash shinai with oil using toothbrush.
- Wrap and leave for at least 5 days, maybe longer (~3 weeks)
- Like so: http://sjmk.co.kr/soojae/rev.php?name=bbs_soojae_rev&mode=read&idx=150&nbpage=1