Retiring Hardware

This weekend, for the first time, I found myself having to make the decision to retire a piece of climbing hardware at the YMCA where I work. It's a decision I hate to have to make, but consider it absolutely necessary. It was a caribiner of the screw lock variety. The problem was that when you screwed it down, the screw collar kept spinning. To me that indicated serious internal wear on the threads and since you can't inspect to determine how serious the problem is, it must be retired. I took the 'biner home, but am trying to decide whether to cut it or just use it in "non-life safety" applications.