Depth Psychology: Dreaming about filth means you really believe you are dirty (physically or morally) or very plain (physically or spiritually).
If the dream is a sign of feelings of inferiority, seek professional help. But remember, dirt is not always negative (Earth, Manure, Mud) and is often an important symbol of personal growth. [1]
It is possible that this feelings of guilt precedes birth. Some parents refer to early sexual activity for their children as a dirty thing, and this idea could affect the subconscious of the child.
If the dreamer feels repulsion towards filth, it could mean that they do not want to explore certain areas of their own sexuality. [2]
If the dirt comprises oil or grease in the dream, it means attachment to mundane and material objects. Washing one’s clothe in a dream means repenting from sin and washing them away. Cleaning off the wax in one’s ears in a dream means hearing pleasing words.
(See also: Cloth, Dirty face, Garment) [4]