It wasn’t too long ago that a couple of our iPods’ headphone jacks stopped locking when we plugged something into it. Normally you’d hear a little click as it snaps into place, but it wouldn’t click, and eventually fell out if you held the iPod vertically.
With the idea of sending it in for a non-warranty repair or tackle iFixit’s DIY tutorials, I put a toothpick into the headphone jack to see if the pins were bent, instead I found the jack full of debris! I used the toothpick to loosen up the debris, and tapped the iPod on the desk a couple times to get the rest of it out (compressed air works too). After a minute of cleaning the jack, the headphones snapped right in! The click was back and it felt brand new!