Hi,
What is the jack’o lantern item that you earn as a daily reward right now ?
(Sorry, i’m not english)
If you’re talking about the “mysterious …” one, then you can participate in the Jack fight in Agartha (portal with “Happy Helloween” at the Agartha mall entrance) at two minutes past the hour and you get a buff which allows you to open this and receive its rewards.
Unless you are talking about “Jack’s Head” from the rewards bags, that is an item used in the New England wing in your museum in London.
What do we do with the ones we didn’t use during the event?
They will be converted into shards 1-2k iirc