On Tuesday, March 14, 2017 at 5:43:01 AM UTC-4, Pat wrote:
On Mon, 13 Mar 2017 19:19:14 GMT, "Tekkie®"
wrote:


It's called ozone. Use plastic zip ties.

Will do, but it must be more than ozone. The entire bands were
subjected to equal amounts of ozone. Only the parts in contact with
the metal valves hardened. In fact, the rubber bands still in the
original opened package were fine. They saw the same amount of ozone
during those eight years.

If I understand correctly, the rubber band hangs on the valve, the tag is suspended below it. The rubber in contact with the valve has failed while the rest of it remains intact.

We know that stretched rubber oxidizes much faster than unstretched, but you say this part isn't stretched.

Speculating then, the part in contact with the valve is subject to temperature effects and does move over the year as the ambient temperatures change.