We would like to cover our tv that sits inside a niche over our fireplace with a two-way mirror so that you only see the tv when it's turned on, or have a mirror on hinges that swings open. Any advice on either mounting. We're worried there may be too much light in the room during the day to see the tv and we don't want to permanently attach (nail?) the mirror/frame into the wall. Does anyone have advice or experience on either way of hiding the tv?