I think I found the perfect cleaning agent for headphone cushions—velour and similar.
After about three months of use my brand new HD 650 cushions already started to smell a little bit, to the point I smelled the dirt just by wearing them. This is mainly because I have slightly oily skin, and even though I shower 2 times a day my skin is always releasing a little bit of oil, and even people who have slightly oily skin knows that the ear area is a favorite for releasing oil, specially after a night of sleep.
Vanish Power O2 it is.
- Appears to do absolutely zero practical damage to the cushions;
- Leaves zero smell (rare for a cleaning agent).
Here is how I did it:
1. Take a bowl and filled it with 45 ºC water;
2. Add about one and a half spoon of Vanish (powder) in the water;
3. Leave the cushions soak in the water for 15 minutes (important: cushion side pointed down, plastic side up);
4. Come back, water will still be warm;
5. Start pressing and releasing the cushions under the water for about 4 minutes, also scrubbing the cushion surfaces gently with your fingers to ensure no oils/waxes remain on the velour;
6. Get rid of the dirty water;
7. Add another batch of 45 ºC clean water inside the bowl;
8. More pressing and releasing the cushions under water for about 2 minutes to clean out Vanish residues from the inner cushion sponges;
9. Throw out the dirty water;
10. Add another batch of water, this time ambient temperature water;
11. More pressing and releasing for about 1 minute under water to ensure no Vanish residues are left inside the cushions;
12. Take the cushions out of the bowl and press them between both hands flat to get rid of the water inside the cushions;
13. Press them various times over a clean dry towel, with each press executed in a different "unpressed" spot of the towel, to remove more moisture from the inner sponge;
14. Leave the cushions with the sponge side pointed closely to the front of a fan for a few hours;
15. Cushions will be looking awesome, dry as phuck with absolutely zero smell.
One important thing: There was zero practical difference in sound after having washed them. So don't worry about that.
Another thing: If your cushions are a little bit flat, these washes actually help the inner sponges return a bit to their original format, but don't expect miracles. This happens because micro particles of oil get trapped on the surface and a little bit inside the sponges. These oils behave as waxes that get harder over time, helping the sponge memorize the flatter shape of the pads from when you have the headphones on your head.
I have experience washing headphone cushions from the time I had my Philips SHP 805, but this is the first time I used Vanish, and it was on my never-washed HD 650 cushions. I'm very surprised by the superior results of Vanish. I just used washing machine liquid cleaning agents before, but I hated the "good" strong and lasting smell they always left on the cushions. I could always feel that smell when I put my headphones on.
Almost monthly careful washing of my SHP 805 cushions made them last for 9 years and they only started to look slightly damaged last year, but of course they are a little flat. That was a 40 USD headphone bought in 2005, just so you have an idea.
For me it's a must to wash these cushions, because like I've said before they start to smell pretty quickly on my head. The fact that I have my HD 650 on for 10 hours every day accelerates a lot the time it takes for them to get dirty.
I had lots of questions about this in the past and never found specifics (detailed step by step) on the internet and I had to figure it all out by myself. My method might not be the best, but in my opinion gives exceptional results.
Feel free to ask if you still have a question about this matter.
Hope this helps.