NYE was only 4 and a half months ago! Only you know the usual dynamics of your friendship, but to me, that is really not a long time to go without seeing or talking to a friend, even one of my better friends.
Still, it's a long time to hang onto forgotten items, so, it's not unreasonable to send a text or FB message to say, "Hey, I'm trying to declutter and I realized I still have your things. I'll be driving right past your place on the way out tomorrow, so can I drop them off?"
This way, you really can make it quick without sounding like you're trying to get together (just in case she really is avoiding you). If you can't get a hold of her, feel free to drop it off at her doorstep with a note (unless she lives in an apartment that requires buzzing an intercom to get in).