Can anyone with experience with DJI Phantom 3 drones please give me advice on how to unscrew the built-in lens filter that ships with the Phantom 3 4k? (It's the same camera and filter on the Phantom 3 Professional and the Phantom 4). I need to remove it to attach ND filters or it is useless for shooting video in daylight. The filter that shipped with my drone is so badly stuck that no one can get it off. I tried unscrewing it myself with rubber gloves, a rubber band, a rubber strap wrench, a rubber jar opener the same size as the lens, and finally with channel lock pliers. More recently, I tried lubricating it with silicone gel and repeating the above techniques. That just made it impossible to get a good grip on the filter ring itself. I've also taken it to three local camera stores/repair centers, and they all tried to unscrew it with a rubber gripping cloth but didn't get anywhere. They weren't willing to try anything else because they were too worried about liability for damaging the camera or gimbal. I can't find any repair places that are experienced with drones or willing to break this filter off the lens with specialized tools. That is probably the only thing that will work at this point. Does anyone know of a drone repair specialist in or near the San Francisco Bay Area who could actually get this lens filter off for me? I've already tried everything else I can think of or have read about.