Abstract: In a cleaning system for toilet bowls comprising a cleaning container for accommodating a cleaning preparation which is designed to be mounted on the rim of the toilet bowl and which is provided with correspondingly arranged openings for part of the flushing water to pass through, the invention enables the cleaning container to be filled with granular active substance without spillage and/or granulate to come into contact with the skin. In addition, the cleaning container is designed so that in the in-use position, its contents are substantially inaccessible to young children despite the refill facility.