In an interview with CBS News on Sunday, Dick’s Sporting Goods CEO Ed Stack revealed that his company had destroyed about $5 million worth of the semi-automatic rifles in its inventory. Stack made the decision to remove all military-style weapons from the company’s stores in response to the 2018 mass shooting at Marjory Stoneman Douglas High School in Parkland, Florida. Rather than returning the guns to their manufacturers, Stack opted to reduce them to scrap metal. So how exactly do you destroy large quantities of guns?

By cutting, shredding, melting, or crushing them. In his new book It’s How We Play the Game: Build a Business. Take a Stand. Make a Difference, which was released Tuesday, Stack writes that Dick’s “sawed $5 million worth of rifles.” (Slate has reached out to Dick’s requesting more details on how it sawed the rifles. We will update this piece if we receive a response.) Yet Bureau of Alcohol, Tobacco, Firearms and Explosives* guidelines for properly disposing of guns, which are based on the National Firearms Act of 1934 and the Gun Control Act of 1968, dictate that saws are not an adequate tool for this task. The ATF instead recommends using an oxyacetylene torch to sever a gun into pieces. It specifies that each cut must be made at an angle and remove at least a quarter inch of metal. The cuts also need to pass through three critical areas: the “forward wall or barrel mounting area,” the rear wall, and the area containing “a critical fire-control-component mounting pin and/or the slot in which the operating handle reciprocates.”

The ATF also notes that shredding is an acceptable alternative, which is more efficient given a large number of guns. In 1993, the Pentagon reportedly began using a shredder nicknamed “Captain Crunch” to dispose of old and worn guns. Captain Crunch is housed at the Anniston Army Depot in Alabama and can shred weapons made of steel, wood, plastic, and aluminum. Personnel with the Defense Logistics Agency, which is part of the Department of Defense, can place up to 2,500 firearms per day onto a conveyor belt that feeds them into Captain Crunch’s interlocking blades. The personnel take a blowtorch to the remains to ensure none of it can be used to construct a gun. They sell the scrap, which generated $12 million per year by 2007. There do not appear to be any public videos of Captain Crunch, but below is footage of a similar shredder that the company GunBusters uses to destroy guns confiscated by St. Louis police:

Melting is also an effective, ATF-approved method for disposing of large quantities of firearms. Every year, the Los Angeles County Sheriff’s Department* holds a “gun melt” to destroy thousands of weapons that officers confiscate. The department hauls the guns in a truck to a steel mill. Front-end loaders then transport the guns to a furnace set to about 10,000 degrees, roughly the same temperature as the surface of the sun. The melted remains are then refashioned into reinforced steel rebar for freeway repairs and other construction projects in California, Arizona, and Nevada. You can watch a video of the process below:

The fourth way to destroy guns under ATF guidelines is to crush them. The Long Beach Police Department began using a $20,000 hydraulic press called “The Crusher” in 2015 to squash weapons under 2,500 pounds of pressure. The press can crush three firearms at a time and up to 40 per hour. The Crusher can handle weapons ranging from the size of a pocket knife to that of a .50-caliber rifle, and the department is also using it to dispose of swords and brass knuckles. Long Beach police then sell the scrap metal.