Elastic and ball-point pens.

[DTisme]

I am amazed how often I throw away ball-point pens here because they've dried up to nothing. And even more amazed how often I find an elastic waistband pau. Today, the foam in one of my swimsuit "bras" disintegrated into a nasty powdered mess. Yet another surprise in the tropics. It's never happened anywhere else I've lived. What gives? Any chemist or physicist out there to explain it?