My trusty Logitech G633 headphones have intermittent sound in on headphone, the culprit is the 3.5mm -- PC slider switch (it's a bit weird as it is only ever set to PC). I assume there is some dust or a contact issue. I can get thing working in both ears by fiddling with different pressures on the switch but was hoping for a permanent solution. I've tried to blast compressed air in, as well as a bit of CRC, both of which improved things a little but didn't fix completely and it slowly gets worse. 

Any thoughts on quick and easy ways to fix? TIA (Sorry for the grotty image, I did try and make them clean