Figured out how to remove the ear pads - a firm grip on the inside of the pad and then pull - and the headband pad as well.
So I decided to share my experiences of the latter in one quick lesson.
Unfortunately, Sennheiser do not keep the original HD565 and HD265 headband pads in stock. The ear pads are identical to the HD580, HD600 and HD650, but the the headband pads of said models are not as long as the HD565/265.
The HD600 and HD650 headband pads ($10-15) will do, however, with a simple modification.

Upper HD650, lower HD565 (deteriorated foam, flat).

Start by gently prying with a knife between headband and plastic lock on the outside of headband (not between plastic and metal).


Eventually it will come loose from the headband.

Now you can remove the metal band cupholder from the headband, and - by pressing the metal tongues - remove the metal band from the lock. Next step is to remove the old headband. To make up for the shorter length of the HD650 pad I cut out some plastic spacers, as it were from a minced meat package.

So, with the headband open at one end, first slide in the plastic spacer.

Then the headband.

Then you put the plastic lock in place at the other end of the headband, and finally insert the metal band cup holder. Voilà:

One of Sennheiser's most underrated and best "bang for the buck" headphones ever is back in business. Precision of left to right instrument placement in the proper recording is stunning.
Edited by MDR30 - 3/26/11 at 8:27am