40d:Refuse

Refuse is a stockpile meant to designate where certain junk can be placed. A typical refuse pile will hold items like bones, shells, certain corpses, remains, chunks, and any totally worn out items like clothing.

Certain pieces of junk (corpses, chunks) will rot, and emit miasma as any other rotten item stored inside. It is important to know where you want to place your refuse stockpile beforehand, as miasma is a happiness hazard for your dwarves. Designating a refuse pile outside your fortress is good, as miasma will not develop in the open. If you want a pile inside your fortress (you will), separate it from other rooms with walls and doors, this will contain all miasma inside. Alternatively, you can dig an open pit down to the z-axis level most convenient for you. As long as there is no ceiling, it will be considered open area.

It is a good idea to use two layers of doors (i.e. a short corridor with two doors, one after the other). This is to prevent miasma from leaking out into the fortress if a dwarf uses the door at the wrong time.