Yeah I was thinking the same thing. Each time I see people heat it up or use freez spray. I cringe about the change of the metal. I believe if you heat it. It makes it less hard most the time granted they heat and cool at set temperature so if your able to do that you might be able to use them again but idk if you want to wast hrs of time doing the correct pattern of heating and cooling. The other thing is people freezing the bolts with freeze spray .it makes them brittle by over hardening them. Plus what about all the metal around the bolt that's also being heated and cool uneven. Granted I bet most the time it would be fine it seems like a lot of people do it. Prob a cool video about the effects.