Box something off - Idioms by The Free Dictionary

box off 1. To accomplish some task that one has been meaning to complete or take care of. A noun or pronoun can be used between "box" and "off." We'll need to do the paperwork sooner or later, so let's just box it off this weekend. There are a few things we still need to box off during this meeting.

Source: idioms.thefreedictionary.com