Pocket Lint
This item could be obtrained from the drop system. It was released a couple of days before the Pyromania Update in June 2012. After the update, the Pocket Lint was incinerated and renamed to 'Charred Pocket Lint', thus becoming a crafting ingredient for a 'Pile of Ash'.
Pocket Lint
Team Fortress 2 Level 1 Pocket Lint
Is it fabric lint? Navel lint you're keeping in your pocket so you don't lose it? Naval lint brushed from the hull of a battleship? This is pretty mysterious lint.