Gee, I wish I had read this a week or so ago. My boxer decided to chew up a couple glass balls too. But she was violently throwing up, so we rushed her to the vet. The vet took x-rays and ended up keeping her over night because she was throwing up so badly. No glass was ever found. But it did cost us $170.00 when we picked her up the next day. I just wish I had known about the cotton balls.
Thanks for the info!!