I travel a lot. The hours spent droning through the sky can be made more tolerable with an MP3 player and a set of noise-cancelling headphones. Reducing the sound of the airflow and engines is a great relief.

For a year or two, I used a pair of folding Sony MDR-NC5 Noise Canceling Headphones, the ear foam covers self-destructed. I replaced them with old washcloth material and was happy, but the DW thought it looked bad.  I switched to a new set of Sony MDR-NC6 Noise Canceling Headphones.  These worked equally well, although they did not fold as small as the MDR-NC5 headphones.

Over four years of use, the MDR-NC6 headphones started cutting out and making popping noises.  This was not surprising considering the beating they took on travel in my backpack.  It looked like I needed another new set.

The older MDR-NC5 headphones were still on the shelf with the hated washcloth covers.  A quick search online showed a vibrant business in selling replacement ear foams, often at exorbitant prices.  Nowhere did I see ear foam covers made for the oblong MDR-NC5.  I then realized that foam is stretchable and that the shape should not matter.  After another search and some consideration, I purchased 2-5/16" foam pad ear covers that were able to stretch over the MDR-NC5's strange shape.  Problem solved for less than $5.