|This article is about the current version of DF.|
The clean self job is a special job in that it is enabled automatically and cannot be disabled. Dwarves that have been contaminated, be it by dirt, grime, or goblin blood, will take a bit of time off at some point to clean themselves if possible; dwarves that haven't had a bath in a while will do so as well on occasion. They can do this with access to a water source, be it a murky pool, a brook, or a well (but not rivers as they will be swept away). In the absence of such an area, or if the water source(s) are forbidden, they will not perform this job.
Cleaning oneself gets rid of anything on the dwarf, and doing so with a bar of soap in addition to some water has a good chance of providing a happy thought. It is most useful as preventative medicine: dwarves that clean themselves lower their internal dirtiness levels (even more when they use soap) and thus dramatically lower chances of an infection in case they are wounded. Many fortresses, especially ones in evil biomes, include a bathhouse in their design. This is important, because a non-military dwarf caught in a rain of repulsive goo will immediately run to clean themselves, usually by dashing in to the various rotting limbs of an undead creature.