Well, as long as we're getting gross and disgusting...
I keep my whistles in a plastic bowl with an air-tight lid (think Tupperware). It's a convenient way to keep them together and easy to find in my bag. Only problem is, a few months after I started keeping them in the bowl I open it one day and it REEKS! Obviously the cummulative effects of a lot of use and a closed environment. All of this just happened to coincide with a discussion about cleaning your whistle. So...I soak them overnight in peroxide and then again in Listerine (not that I'm worried about catching some exotic disease, but they really did smell bad). And I notice some gunk had come loose and I decided to blow them out to remove any lurking goobers. Man! Did gunk ever fly everywhere! It was amazing. Took a little while to clean it all up too.