Some minhag Chabad questions:
A prominent Chabad rabbi here asked me the following two questions, both of which I need the advice of Reb Moshe or anyone else for that matter who may be able to shed some light on the following: 1) A door which is a secondary external door - it is not the front door per se but is a main door of a building leading to a parking lot which on weekdays is probably used more than the front door as an entrance - should we follow heker tzir or yemin haknisah? I know this is a machlokes in chabad but what do we do lemaasseh in this case particulalry. 2) There seems to be a minhag in Chabad which was more common 40 years ago and less common today - to put a mezuzah in a paper or thin plastic wrapping directly onto the door. (The idea of see through coverings comes from the Remah, I do not think it is relevant to this discussion). I know that Chabad's philosophy was always to use simple cases because the main hiddur should be the actual mezuzah klaf and not the case. however today we h