Destroy is a feature in RuneScape for certain quest-related items, discontinued items and holiday drops that replaces the usual "Drop" option available to all other items. It most often applies to items which cannot be traded.
These items cannot be dropped, but may be picked up if a player has a full inventory upon receiving one. While in the inventory, they can only be destroyed. This option was most probably introduced by Jagex to prevent players from using the drop trick for certain items. Before being destroyed, a text is shown as a final warning to players. When destroyed, these items may (or may not) be obtained again from the place where they were previous located. The only tradeable items with a destroy option are impling jars with an impling trapped inside, Binding necklaces, and Hunter kits.
The destroy option was introduced with the Garden of Tranquility quest.