Sounds like you have a joyful and rewarding life there in Congo. Makes me want to visit!
My first thought was also ziplock bags. Depending on how many you'd like to handle, choose either the sandwich size or the quart size, but be consistent. When containers are all the same and shape, it just feels better organized.
After reading about the bug problem, I agree that putting those bags inside of clear shoeboxes (or similar box with lid) is smart. Of course, you could have your carpenter build a hinged box that closes tightly, but only you know what the critters are likely to do. If he can make a box for you, I'd suggest one that you can carry easily and fit the squares of bags inside, in a way that they lie flat (don't want to have to re-iron them. Label everything with easy-to-read lettering.