The Certers are a random event. Miles, Niles, or Giles present a player with a rotating image of an item, and three possible choices of what it is. If a player correctly identifies the item, they may receive coins, food, or gems, or a Spinnach roll. An incorrect choice will result in the player's weapons and note-able items being noted and the player being teleported to a random location. The certers used to only note items; however, players took advantage of this by dropping any items they wished to remain un-noted and then answering incorrectly, resulting in the certers noting their raw materials and allowing the player to carry more.
History of the certers
In RuneScape Classic, the Certers were employed in Draynor, converting fish, ore, or logs into certificates. When the new RuneScape was introduced, the certers were removed from the game and replaced by the bank note system. Jagex released this random event as a reference to their old trade.