The drop function is the action in which a player removes an item from his or her inventory, replacing it on the ground. A dropped item does appear on the ground where the player was standing, and can be recovered at any time. Every item holds this function, except for certain untradeable items (such as Holiday Items) where the drop function is replaced by 'destroy'. Destroyed items do not appear where the player was standing, and to recover it, the player will have to return to the original source of the item (or a special NPC that replaces them). A dropped item will disappear after three minutes.
There is no limit to the number of items that can fit in one place on the ground. However, items dropped on the ground disappear after a certain time. Tradeable items appear to other players 60 seconds after being dropped, and disappear after another 120 seconds if not picked up.
Drop is normally used to free a space in the player's inventory, whether temporarily or permanently. For example, if a player wishes to bury the bones in front of him, they may drop his coins, pick up and bury the bones, and then recover the coins. If a player receives an item useless to him or her (such as a few gp given out by a Random event), it is often dropped promptly so as to not waste inventory space.
The drop function is replaced by the destroy function in certain items, usually holiday items or items requiring a specific skill or quest, etc. The destroy function is similar to the drop; it likewise removes the item from the inventory, but unlike drop, it does not appear on the game screen and cannot be recovered. Because of this, when a player attempts to destroy an item, they will always get a warning message. The message usually lists possible ways to recover the item as well.
Drop trading is the term given to the trading method by which one player drops an item to give to another player, and, after waiting for the item to become visible, the receiving player picks it up.
Historical drop trading
Drop trading has been used historically as a way of breaking Rule 6 (Account Sharing/Trading), which dictated that no items may be transferred between players of the same owner, usually a main account and a pure. This use of drop trading was used when having two clients opened at the same time was not possible.
Drop trading was used even more before banks that could hold items were introduced to the game. Many players would have "mule" characters, which would serve as an item bank, and transfers would be done through drop trading. This was highly against the rules, and many players have been permanently banned for it although this was hard to catch due to the player not saying anything during the drop trade transfer. However, drop trading is also risky because there is a chance that the items could be intercepted by another player.
In the very early days, this rule was rarely enforced. Well known players often asked for "coal mules" in return for expensive items. It is reported that Jagex started deleting mule accounts some time in early 2001 but stopped due to the chance of an innocent player being deleted.
While the trade limit was in place, only items of small value could be seen by other players.