The Renewable Plugin
icon image for renewable plugin
The purpose of this plugin is to encourage sustainability in Minecraft :)
Now that might sound kinda hippie, but it simply means the Server keeps track of unrenewables*.

When an unrenewable item is irreversibly changed or destroyed due to lava, despawning, or player actions, the server rescues the item.  These rescued items are automatically collected are used to stock the AdminShop, a location at which players can purchase these items back from the server.  This is also how the server makes (in-game) money.  Please see the Economy page for more details on how the server-economy system works.

* An item is classified as renewable if it can be recreated indefinitely in survival without exploiting glitches or using commands.
* Unrenewable items are the (smaller) set of items in the game with a limited or finite supply