When you're pouring your morning bowl of cereal, you might not want the dust that collects at the bottom of the box to mix in with your milk. If you only want full pieces in your bowl, simply use a colander.
This tip is pretty obvious in hindsight, but it's something you might not think of when you're groggy early in the morning. Just empty out your cereal box into the colander, and let the dust fall into the sink. Personally, I enjoy "drinking" the cereal dust once a box is empty (I really hope I'm not the only one), so I might filter it into a bowl to enjoy separately, and save the full pieces for a proper bowl of milk.