Oscar is very food-oriented and will eat almost anything. He also goes crazy for anything that moves (typical terrier). So when we drop something on the floor, he's bound to pounce on it and try to eat it. A handy little command we learned in order to deal with this combination of traits is "leave it." You can start by putting a treat on the floor and covering it with your hand or foot. When the puppy sniffs at the treat and tries to get at it, say "leave it." When he finally leaves it alone, sits back and looks at you, praise and give him a treat.
He's gotten good at this now with treats. We can do the command while dropping a treat to the floor and he'll leave it even if we don't cover it. He's actually gotten good enough with treats that when he's lying down, we can put a treat on his paw, tell him to leave it, and he'll just stare at it until we say it's okay for him to take it. I'll be really impressed if we can manage to put a treat on his nose and tell him to leave it. Given his newfound fascination with paper, I'll also be impressed if we can drop a receipt or something like that on the ground without him trying to eat it. Maybe one day!