Part of the issue becomes what kind of glue has been used. Some will let go more easily than others. That being said ...
Screw a field point into the insert and heat the field point with a flame (candle, cig lighter, etc) This allows the heat to radiate to the insert. Tug on the field point with pliers to remove field point and insert from the arrow.
There still is no guarantee. You still might get the carbon overheated. If hot melt was used it will give up the insert fairly easily. If something like goat tuff has been used it takes more heat and might damage.
Question becomes, do you want to take the risk for 1/2"? Or as Dirty Harry would say "Do you feel lucky today?"