Minecraft wiki entry for Tips_and_tricks, associated text: Many players dispose of unwanted items by dropping them into fire pits, lava, and cacti to destroy the items. But by doing so they risk accidentally dropping something valuable and losing it forever, like a diamond pickaxe. So rather than destroying the items, a smarter method of getting rid of items is to drop them into a hole with a trapdoor over it, eventually the items will despawn. By doing this you can easily recover items that you accidentally drop; plus you can't pick up items through closed trapdoors so you don't have to worry about accidentally picking up unwanted items.