One inbox to rule them all
A pile of inner stapled A5 is slightly womb... when there are more than 5 big documents stacked, it can easily fall. And I had several piles over my desktop: To read someday (better sooner than later), current references (papers I am using more than twice a week or so) and past references (the ones that were in the previous category but have not used in a while).
To solve the stacking problem I took 3 paper folders, these that come in different shiny colours and folded them into the easiest origami box, which serves pretty well as A5 inboxes. As an added benefit, if you fold another box following the same procedure you will have a lid for your inbox, allowing you to store it neatly.
The diagram is below, click to enlarge it. It is suited to be printed in A4, but I think all steps would also work in Legal sized paper and paper folders. Below it you will find some pictures of the procedure, just in case the diagram is not clear enough. Enjoy your origami inbox!
Click to enlarge