Historically, you might have seen more practical throws years ago, including food items and fresh vegetables - that's undoubtedly illegal now; Some laywer probably got hit with a bundle of radishes and that was the end of that Krewe ("Were you injured in an accident with a Zulu Coconut? Before you accept a quick check, Call ME!).
There's no telling what you'll catch when you put your hands up in anticipation of the hopefully generous folks on the approaching float. I've seen people throw everything from empty cardboard boxes and beer to money (you're likely to see some people throwing pennies from the truck parades on Mardi Gras day - now there's an idea that I hope catches on...) Now let's talk about this STUFF, the junk, the beads and plastic thingies that fly through the air. To the locals, some of these things are the bane of Carnival - plastic harmonicas, fake dog-doo, tiny footballs, whistles, even mock hand-grenades, guns and cigars. Considering the half life of these trinkets is probably somewhere in the area of several millions of years, one can only wonder what happens to them? Haven't they made enough of these things already?
Ironically, about thirty seconds into Ash Wednesday, much of these previously treasured items become instant fodder for the inevitable spring yard sale. It might be interesting to note the life of a decent Mardi Gras throw - locals catch things from one year, pack them into Schwegmann shopping bags and stick them in the attic, then give them to a family member or friend who might be riding in a parade the next season - and the cycle continues... For all you know that pair of purple beads around your neck has been through a dozen seasons, and was previously stuck in a tree, thrown into a tuba player's horn or dangled from King Kong's fangs in Bacchus.