Shooting it with a .44 Magnum. For best results, you'd have to get Dirty Harry to come over and do the shooting himself. I guess that's about as macho as flashlight torture tests go. Oh yeah and maybe you ought to have some death metal playing in the background.

Maybe less macho but more down to Earth would be just using that flashlight for about a year and see how it performs. If you're not a hardcore user, give that light to someone who is (military, law enforcement, firefighter etc.). You're likely to get the very best kind of feedback that way.

Boiling, freezing, choking, smashing, throwing, chainsawing, lightsabring a flashlight and finally running it over with your car is all good but I fail to see much real-world application.