I've a lovely Retina II with a front door that doesn't like to open easily. When I press the release button on the camera base plate, the door unlatches easily enough, but then I have to gently pry it open with a fingernail. It doesn't do the leatherette covering much good. I don't want to disassemble much of the camera; everything else is functioning quite well (except of course for the rangefinder, but that's not a big issue with me). Is there any particular part or area that can be targeted for cleaning or lubrication?