In dreams, seeing ashes is generally considered a symbol of illegal money or loss. It can also indicate funds coming from the government or authorities. If you dream of ashes, it suggests the possibility of some financial changes in your life, which could be significant for you.
From Imam Muhammad Ibn Seerin's Dictionary of Dreams According to Islamic Inner Traditions â entry "Ashes" (page 22).
In a dream, ashes represent unlawful money or they could mean burns. Ashes in a dream are also interpreted to mean money one will receive from someone in authority or directly from the government. Seeing ashes then mean difficulties or toiling for no benefit in the service of a person in authority. Ashes in a dream also mean vain talk, or a knowledge one cannot benefit from. If one sees himself carrying a container filled with ashes in a dream, it means that he is engaged in falsehood, backbiting or in acquiring useless knowledge. If one sees himself blowing air into cold ashes in a dream, it means that he will engage in futile undertaking. Ashes in a dream also denote sadness, sore-eyes or heedlessness. Ashes in a dream also mean quelling the fire of war, suppressing upheaval, or attaining peace. Ashes which are collected from baking in a dream represent charity, or curiosity. (Also see Coal) 'Ai.b,ura: (10th day of Muharram; Anniversary of the martyrdom of Husain at Kerbela.) If a descendent of the blessed family of God's Messenger, upon whom be peace, sees himself on the day of 'Ashura in a dream, it means that he may have to face an adversity. If anyone else sees that in a dream, it means the opposite.
Note: Islamic dream interpretation depends on the dreamer's circumstances and state. This is a general guide drawn directly from the source book.