A refill cartridge disposable within a spray bottle during usage thereof. The refill cartridge includes a cartridge body defining a cartridge reservoir. The cartridge body includes first and second openings, the second opening being defined by a projection of the cartridge body. A cap is connected to the cartridge body to substantially cover the first opening. The cap includes a cap base having a primary opening. A cap boss is connected to and extends from the cap base and defines a passage concentrically aligned with the primary opening. The refill cartridge additionally includes a plug having a plug body including a plug neck and a flared portion, with the plug neck defining a distal end. The plug is engageable with the cap and the cartridge body and is moveable relative to the cap and cartridge body between a sealing position and a dispensing position.