If you have alot of them, there's a method described in "The ABC and XYZ of Bee Culture". Stack them up and throw a wad of newspaper inside and douse with a little kerosene or lighter fluid, light, put a lid on and let burn for maybe 15-20 seconds or until the insides are lightly charred. knock the stack over to douse flames. The book describes it in pictures. Very simple. AFB spores can live a loooooong time. 3 decades or more. Good to be careful, but chances are, you'll be cleaning eqiupment that doesn't need it.