Abstract: A canister is adapted to be hung in a toilet tank with the lower open end below the normal water level in the tank when the tank is full. A reservoir is situated at the upper end of the canister and communicates with the main portion of the canister and an evaporative liquid is placed in the reservoir. A divider separates the reservoir into two portions, one portion communicating with the main portion of the canister. As the water in the tank empties, air is drawn through the liquid and evaporates some of the liquid and when the tank fills, this air is once again bubbled through the liquid and expelled into the tank, it being understood that the evaporative liquid is preferably provided with deodorant properties.