Several dogs have eaten stuff lately, and I recall a couple being told to feed the dog bread, so it will pass easier. If it is not sharp, it should pass but could take awhile. Keep on eye out and check poop. If he starts vomiting, drooling and drinking excessively-then he needs to get to the vet pretty quick.. It could take a week or more to pass. Hope he will poop it out.
You probably should call the vet in the morning, and see what he thinks.