It all depends on how many primers you need to get rid of. My favorite way to dispose of them is to fire them in the gun. Some dented cases can be resized enough (with primers in them and decapinng pin removed) that they can be chambered. Sometimes I would use a bench vise to hold the case and use a pin and a hammer to set the primer off. When I do that I wear heavy leather gloves, a full face shield and have a fan in the window working on exhaust.