I have been buying lighting gear, new and used for location use. I am uncertain about the proper refurbishing of some of my fresnel fixtures. Cleaning out the accumulated dust and debris is obvious, replacing worn/damaged wiring and sockets, is as well. Most of them have their interior baffels painted (coated?) black. I would have to believe that this is to reduce the amount of light bounced around inside, eventually leaking out thorugh the vent slots. Two which I recently acquired have a very oxidized white coating inside. They were made by Bardwell and the current owners of the company are not very helpful in providing information on a discontinued fixture. Should I spray it with high temperature black? Leave it alone? Spray it white again?