He'll "process" them on his own and more than likely be fine. Anything soft like that gets broken down and passed. It's the stuff that doesn't break down you need to worry about. My mother's dog eats plastic and socks. He chewed the lid off of a prescription bottle in under a minute!
We had to sit on him and pry the pieces out of his mouth. The vet says you have to watch out for things that will poke their insides or get stuck. And you have to watch out for things that will poison them. Which, sadly could be any piece of plastic now (thanks China!).
I say watch him and do the vomit trick if he starts to act funny. (Hey! That sounds like good advice for DUmmies too!)