Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
Washing clothes in a dream indicates repentance, payment of debt, and removal of worry. Washing the face indicates modesty and righteousness of affair. Washing the dead indicates praying for them.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
Washing indicates relief and salvation. Washing a utensil indicates the righteousness of the servant.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
Washing is interpreted as goodness and blessing. Whoever sees himself washing something, his affair will become righteous.