Hold off on that peroxide!! Had a doxie swallow a nylon stocking one time. The vet said if it was LESS than ONE HOUR, we could induce vomitting, but after that it was too late. I would call the vet. It may just pass through, but it could get twisted up in the intestines.
Our one dog got a piece of corn cob out of the trash one time. I had to watch to make sure she was going and not blocked up. I was outside at night with a flashlight watching her go. I felt like a freak, but you do what you gotta do.
4 or 5 weeks later, she puked up the corn cob. The vet couldnt' believe it laid in her gut that long.