DIY Self-cleaning glasses case

I wanted a small and flexible case for my music-reading glasses. Rather than trying to find one in a store, I took matters in hand and used materials I found on and around my desk. If you want to make one, here's what to do:

Now every time I switch glasses, I get a freshly-cleaned pair to put on. I imagine there could be many variations on this theme that don't involve tape, but the tape does provide a good deal of stability. An extra layer of a sturdy fabric would probably work just as well.