Headphone foam question...

Yes, this is out there, but I'll ask anyway...
My second set of good headphones I travel with and use is from Bose.
As with the previous set from Sony, the foam that goes on your ears has begun to flake away and every time I pull them out of the bag in my backpack, tons of flakes go flying, and are also stuck to my skin when I'm done using them.
Anyone know why this happens and what I can do to keep it from happening when I use AMEX points to get a new set of Bose?

 

The leather/leather-like substance tends to dry out and then it makes a mess not only because it's coming apart but also because it leaves a residue on you, too.

But for all the talk about replacement parts I had heard from Bose, I have yet to run across a site that had them ready to purchase for either the TriPort or the QuietComfort lines of headphones.

 

I have a set of Sonys (MDR-V6) that I've had for nearly 20 years. This same thing happened and I was able to find replacements online for very little money; think it was B&H.