ive done the oven method. Works well. Just keep an eye on them and make sure you dont do over 200. I even kept the door to the oven open cause even 200 is sketchy IMO. Youd be surprised at how easily the cookie sheet will melt to the back side of the light..

Problem with a heat gun is most of the time it cools down too much by the time you are at the other side of the light..