The present invention relates to an aerosol device including: —a container containing: —one or more propellants, and--a composition including one or more sebum-absorbing powders with a sebum uptake of greater than or equal to 35 m1/100 g, the propellant(s) possibly being present in the composition or, in the container, separate from the composition, —an aerosol device for dispensing the said aerosol composition, including a diffuser equipped with at least two, and better three, spray orifices (22). The invention also relates to a process for the dry-washing and cosmetic treatment of keratin materials, including a step of applying to the hair the cosmetic composition, sprayed from the particular aerosol device.