Minecraft wiki entry for Witch_farming, associated text: One Option for grinding Witches is to use 24 Minecarts as an entity crammer trap. The downside is that Minecarts, especially 24 of them updating when the witches get killed create a lot of noise. In order to make this form of grinder, dig straight down 4 blocks and hollow out 4 blocks ahead of you to create a 2 tall, 4 block long corridor. Hollow everything except the block directly under the water streams by one block downward and place a rail on the block left behind. Place all 24 minecarts, then a full block in front of the rails so the minecarts cannot escape when the farm is closed up. Take the block underneath the block with the rail and 24 minecarts on it out. Dig 2 blocks down on every block except for the one where the 24 minecarts are now resting. Place the chests one block away and two blocks below the one that is holding the minecarts above. Place another rail on the hopper and a slab on each side of the rail. Place the hopper minecart on the rail. Place an upside down stair in front of the rail and there you have it.