I checked the official Gamagori City website but found no explicit sorting instructions for "gas cylinders" (gas containers). Similar items include spray cans and cassette gas cylinders (cassette gas canisters), for which the following guidelines are provided: ・Empty spray cans completely without puncturing them, then place them out for resource collection on resource collection days (effective April 2018). When releasing gas, do so outdoors in a well-ventilated area. Check if the product has a gas release function. Cassette gas cylinders may not have a gas release function; if you cannot use them up, consult the seller or the Japan Gas and Oil Equipment Manufacturers Association (contact information). ・Information exists regarding bringing items to Gamagori City's Environmental Cleaning Division (Clean Center), but since the specific handling of gas cylinders is not explicitly stated, confirm whether they can be brought in. Therefore, the final handling status is "Confirmation Required," and general disposal guidelines are added below: For general gas cylinders (propane, oxygen, etc.), since handling varies by municipality, the following is recommended: 1) Containers holding flammable gases or high-pressure gas are classified as hazardous materials and cannot be collected. Contact the city's Environmental Cleaning Division in advance to confirm whether the Clean Center will accept them and to verify the procedure. 2) For small, empty cassette cylinders or small containers, either use up the contents following the instructions or contact the seller. Dispose of them according to the method specified in advance (may be treated as recyclable resources). 3) Large, high-pressure gas cylinders often require disposal as industrial waste or through a collection service. Contact a specialized collection service or the original seller for pickup, or consult the City's Environmental Cleaning Division. Important: Follow the final instructions provided by the Gamagori City Environmental Cleaning Division.