If you ever see mini-M&M's in the small plastic tubes, the tubes 
are perfect for holding a soprano mpc (no lig, cap...).  Might even 
work for some metal alto pieces - never tried...

I put a cotton ball down at the bottom and put the mpc in tip first.  
The cap snaps shut and comes in cool colors!

Cheap as heck, works like a charm, and chocolate to boot!

And even after washing it out, it retained a mild chocolate smell 
that can get picked up by the mpc if you leave it in there long 
enough...

Definitely want to make sure the mpc is nice and dry, though, as 
the container is basically air tight.  Maybe drilling a few holes in 
it...

Flavo-mpc!