For obtaining Key Molds see: Guide:Harvesting Key Molds,
Dungeon Key Molds are extremely rare Hardmode items used to craft Dungeon Keys for Dungeon Chests. When in hardmode every enemy has a 0.025% (1 in 4000) chance of dropping a Dungeon Key Mold. The type of Dungeon Key Mold that is dropped depends on the biome you are currently in (Jungle, Corruption, Crimson, Hallow or Snow). Farming these molds can take multiple play sessions.
Biomes can be mixed - any of the designs below can be upgraded via biome-respective blocks to drop certain, or all, of the molds.
During a Blood Moon or similar events, travel to the biome you want to find a mold in. The massive amount of enemies will help you to get the mold. File:Grinding box.PNG
An example
Meteor Heads spawned by a Meteorite biome (artificial or otherwise) can also drop the mold for the biome it is contained in.
It is also possible to make a potential AFK farm by taking advantage of the Leaf Crystal granted by the Chlorophyte armor set. The crystal will automatically destroy any meteor heads in range with a single hit, resulting in very minimal effort on the user's end.
Another alternative, is to use the Pygmy Staff or Raven Staff in conjunction with Tiki Armor or Spooky Armor, confine yourself to a small location where the minions can't escape, and let them do all the work. Placing and holding a water candle and using battle potions from time to time helps immensely with this method.
You can also use a box with the Spiky Ball traps from the temple and meteor heads
The most hassle-free way would be to have Turtle armor equipped and immerse your bottom half in honey or water. Though you will need an hp regeneration method: Campfire, Band of Regeneration etc.
It is a very easy way to simply use the Spiky Ball Trap method and keep your computer running while you go and do something else. Check back in a few hours and you might have at least one mold. Sometimes a mold will drop quickly, other times it will take several hours or days; it just depends on luck.
Notes
Unlike what you may expect from a mold, it is consumed in the crafting process.
Even while taking use of farms these molds are an extremely rare drop and may take anywhere up to 7+ hours to farm. If you run a dual-screen it is advised to run Terraria continuously in a window on your secondary monitor and glance over every now and then to check for mold-drops.
For single screen users, double click the windows task bar (that large thing on bottom of monitors) of the terraria window to minimize the game. It'll still run regardless of pause setting (? ), but sound will still play and mouse clicks still function. (old trick for statue farms)
Another way for single screen users is to run the dedicated server software. While in the multiplayer server minimizing the screen will not pause the game, allowing you to AFK farm.
