I live in toronto, and the bais yaakov here started a clothing drive for E”Y a few years ago. Its really amazing – a girl had the idea and it really took off! all hte students pitch in to sort, pack,etc. maybe you could contact them about doing it in your area. also, there must be second hand stores (jewish or not)to sell your stuff at.
or, donation boxes, jewish or not. so many people could use what you don’t want!
as for nyc, don’t you have gemachs? check your directory.