[95bcwh]

Some claim it improve transparency, soundstage

[Big Red Machine]

Only the 'fresh out of the field' works.  Any man-made fiber is full of bad tone and should be avoided.

(troublemaker, aren't you?!)

[IronLion]

The best method is to use the lint balls that come off your socks, so long as they're made of 100% wool.  Soundstage explodes around you this way, but the lint must be recharged every month with new lint from your socks. 

[martyo]

I thought it was navel lint. 

[BrianM]

Dammit, I was putting the stuff in my ears, to facilitate smoother sound wave to auditory receptor coupling.

[95bcwh]

ok, sorry.. I should have provided the link of the company selling this stuff:
http://www.acoustic-revive.com/english/psa100/psa100_01.html

And here's a bored guy who recently did the experiment with cotton wool, here's what he said:

I was quite boring today when i came across Acoustic Revive website....where they are selling some cotton wool to reduce standing waves, which is claimed to improve sound quality.

Hence i did a small experiment. I use some normal cotton wool on speaker cables, interconnect, powercord as how they would use the Acoustic revive product.....

Wow....i was quite surprised.....the soundstage suddenly become clearer and more transparent....in short the sound opens up and is more detailed....quite amazing....

Maybe normal cotton does absorb standing waves too......