Washing is read as clearing away — guilt, a bad day, an old state. Tradition takes it as the wish for a fresh start. Washing your hands is linked to wanting to be free of responsibility for something, while cleaning a house points to putting your life in order. Dirt that will not come off is read as a feeling or memory that lingers. Washing someone else stands for care and devotion. Doing laundry carries the old image of sorting private matters. It can help to notice what you most wanted clean in the dream.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.