Our first cat loved the plastic strips off frozen orange juice cans, but none of our subsequent cats has been interested in them. A warning on cats playing with string: be sure they are not swallowing it. Our male cat swallowed some string when he was about a year old, and he had to have it surgically removed, along with a piece of his intestines. Also, someone at work had a cat who swallowed thread, with the same result. The vet told us that cats have "barbs" on their tongues, which make it difficult for them to get the string out once it starts going down, so it will just keep going in until they bite or break it off. Our cat, now 7 years old, seems absolutely fascinated with chewing string; we really have to watch him. One morning I was in the bathroom flossing my teeth, and he got up on the sink, and was standing on his hind legs in the bowl, with his paws on my chest, looking into my mouth. It looked so funny in the mirror, with this little round cat head in front of my face! But, I am really careful about discarding the floss, so he cannot get at it!