Here, one of a major Magewappa manufacture Odate-Magewappa in Akita prefecture (Northern part of Japan) PV made by Odate-Magewappa Cooperative Association.
However, Magewappa Bento Box is less sealing. You have to be careful to carry when you put wet dish in it. Generally most of it cannot use microwave oven and dish washer.
Traditional Magewappa was made by plain wood. But for easy to use recently coating products are common. Some manufacture still make traditional, some products use plain wood for inner side.
Delicate plain wood seems to be hard to deal but you don't have to worry so much. Just to wash with hot water and wipe with a towel then dry inner side up.
1. Immerse with hot water about 10 minutes (depends on food sticking)
2. Rub the sponge with the grain.
3. After the removing inner sliminess, pour steaming hot water to all over to heat up Magewappa.
Then wipe with the towel and dry inner side up.
Note: Drying inner side up is important!
Seasoning Magewappa :
Wet inner side with water and wipe with a towel before putting cooked rice for the first several times. After several month cooked rice will become less sticking without wetting.
Use dish detergent diluted with hot water to remove oil.
Coating materials use more easy use dish detergent usually and just wipe with towel. (Recommend not to use cleanser or scrubbing material. Coating is not so hard as glass or pottery)
Note: This description is general way to use. Don't skip to follow the manufacture's instruction.