generally not worth to bother.
but.. truth is.. you never know who needs what name and how much they'll pay for it.
so.. its entirely up to you.
but if you will do like most do and offer expiring soon or expired domains for like bin $2.. then maybe ask yourself instead if its not better to let them sit on external auctions or parked page for those extra 30-40 grace period days.. and take a chance on selling one of them at least for XXX or whatever figure enduser may pay .. which we all know can be anything at all.
other than this, if you decide to post them on np for sale.. make sure anythign expired or expiring within 3 motnhs says so in auction. otherwise, if it sells and you don't say it, np rules will force you to pay for renewal for the buyer... and there will be nothing you can do about that, if you want to keep your np account rule violation free.
cheers