A selectively attachable attachment device for a steam appliance is capable of delivering a mixture of steam and a cleaning additive for cleaning surfaces. The attachment device includes a member that can be coupled to a steam source, and a housing configured to receive the member. The member and the housing include complementary tabs and detent(s) such that an adjustable spacing may be maintained between the steam nozzle and the additive nozzle. The adjustable spacing permits control of the rate at which cleaning additive is added to the steam.