Im trying to remove the nipple from the invacare oxygen tank and i cant seem to figure out how.iv read you just unscrew the side and it will come off. not in my case though. nothing happened when i unscrewed the side. and there is barley any room to grasp the brass nipple. i have pictures so you can see what im talking about. if anyone has done this before or could shed some light on what i need to do that would be greatly appreciated. this is the only thing i need to get my homefill filling my k tanks.