I have the Nine8Six projector headlight conversion from this
thread in the DIY section. I was chicken to do it myself so I had it done. But in that thread are these instructions. See the section on baking the headlight in the oven. You want to put some wood in the over and put the headlight on the wood, not directly on the metal grates in the oven. (Even though you only want the lens).
I would attach those instructions here, but they are a pdf and I can't attach that through the photo upload feature.