NOVELTY - A composition comprises hydrogen peroxide, an inorganic acid and/or an organic acid, a chelator, an anticorrosive agent, and a surfactant.    USE - Composition is useful as one-component, liquid concentrate disinfectant for reducing microbes e.g. virus, fungus, mold, slime mold, algae, yeast, mushroom, and bacterium on substrate, killing or inhibiting microorganisms on substrate, and disinfecting substrates e.g. metals, plastics, natural rubber, synthetic rubber, glass, stone, grout, fiberglass, wood, concrete, construction product, and building products in hospitals, physician's office, medical clinics, medical facilities, dental office, dental facilities, airports, schools, pet stores, zoo, children's day care, elderly nursing homes, museums, movie theaters, athletic facilities, sporting arena, gymnasium, rest rooms, bathrooms, shopping centers, amusement parks, churches, synagogue, mosques, temples, restaurants, food processing facilities, food manufacturing facilities, pharmaceutical companies, hot-tubs, sauna, and clean rooms, and medical equipment, medical device, surface in medical industry, dental equipment, dental device, and surface in dental industry (all claimed).    ADVANTAGE - The composition is non-corrosive and non-toxic, effectively reduces, kills and/or inhibits microbes on various substrates, and has excellent long-term stability. The composition effectively sanitizes a substrate, thus simultaneously cleaning and disinfecting the substrate. The composition is highly compatible with common materials of medical devices including endoscopes and automated endoscope reprocessing systems including stainless steel, ceramics, glass, plastics, and elastomers.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) kit comprising an enclosed container comprising a removable closure, the composition accommodated inside the enclosed container, and a printed indicia provided on the enclosed container;    (2) method of reducing number of microbes on a substrate, which involves contacting the substrate with the composition for a sufficient period of time effective to reduce the number of microbes on the substrate;    (3) method of killing or inhibiting a microorganism, which involves contacting the microorganism with the composition for a sufficient period of time effective to kill or inhibit the microorganism; and    (4) method of disinfecting a substrate, which involves contacting the substrate with the composition for a sufficient period of time effective to disinfect the substrate.