- Festive Winter Crates first appeared around Christmas of 2010. They were given out and removed if unused from backpacks (when going in-game) on December 31, 2010.
- Refreshing Summer Cooler (crates) first appeared in the summer of 2011 and had a similar usage requirement. They were then removed in July of 2011 from backpacks when players went in-game.
- Naughty/Nice Winter Crates which most of you are familiar with just came out this past Christmas and unused ones have since been removed from players backpacks when going in-game.
Moreover, think of it this way. To keep them from being sucked out of your backpack and back to Valve software headquarters you would need to have at least 2 accounts. One would either need to remain unused in perpetuity OR you would need to trade these crates between the accounts before going in-game. If you've got a short attention span or just plain forgetful collecting these crates may not be for you. Also, keep in mind if you chose to keep them in one unplayed account you would lose out on your drops over time, adding up to some very expensive, unusable crates.