A solid composition including calcium and/or magnesium hypochlorite, a builder (e.g., one or more of carbonate, bicarbonate, sesquicarbonate), an acid, a water-soluble polymer, at least one anionic surfactant, and optionally, a hydrotrope. The composition does not include any potassium hypochlorite, sodium hypochlorite, lithium hypochlorite, N-halogenated compounds, peroxides, persulfates, hydantoins, isocyanurates, or carboxylic acids that also have hydroxyl, amino, amido, imino, or imido groups. Upon dissolution of the composition in water, the calcium and/or magnesium hypochlorite and acid react to form hypochlorous acid. The use of hypochlorous acid, rather than direct use of an alkaline or alkaline earth hypochlorite results in a composition that is typically acidic rather than basic, and that results in improved cleaning. The composition is particularly suited for cleaning and disinfecting dentures.