My favorite "recycled" IEM case so far
Icebreakers mint plastic container. Its small, flat, rigid, and you can take the labels off to make it look plain. Gives you plenty of room to label them too, in case you have multiple IEMs. The white top separates from the bottom so you can wash it out completely before putting your IEMs in there. I especially liked it because it has a pop-up opening on both sides. You could open the small one for the mini-plug and the big side for the buds and leave extra cable coiled int he container. that only really works for stationary use, not in pocket. Its basically free since you are getting the mints too...which arent half bad.