I use mouth calls a lot for elk and turkey.  I always had trouble finding a container large enough to carry 2-4 calls, that would let them breathe so that they weren't spit covered hours later.  Wife brought home a plastic change purse, the kind you squeeze from both ends that is oval shaped.  I used case neck reamer to sharpen a .30 carbine shell and when it was sharp, punched several holes in the plastic with a hammer and the shell.  Voila, a quiet container, that lets the calls breathe, doesn't rattle like the hard plastic ones when there is only one in there, and easy to access in a pocket!!