This is the physical equivalent to the mental gathering or Mind Sweep. It is about searching your physical environment for anything that does not belong where it is and put it into your in-basket. You will be gathering things that are incomplete, things that have some potential decisions for action tied to them. They all go into in's, so they'll be available for later clarification.

Like the mental gathering, this is usually done during the initial implementation process of the methodology, and also on any occasion when you fall off the wagon.