A box like that would not be structurally sound, and finding a place to store it would be a challenge, so I have to think outside the box. How else can I keep this flat and avoid folds, especially on all those fragile places where the strings are bare? Well, if this was a linen cloth with bead embroidery and it was 1'x4', I would find a way to roll it. So let's roll it. First, make a roll:
This is a regular cardboard tube from toilet tissue (1st rule of museum-keeping on a shoestring: never throw anything that's clean and dry away right away - you might need it). I wrapped the tube in acid-free archival tissue, extending the ends a good long way to make the whole thing longer. When I started to roll the belt loosely around it, I realized right away it was going to make a high narrow lump if I rolled it like I would a square of cloth.
What next? How does a band of trim not create a lump on a tube? Roll it at an angle, so it spirals around the tube! It took a few tries to get the starting point and slant right, but eventually I got that sorted out and it worked out exactly how I wanted it to work.
I like that you can see the shadow of the other layers through the tissue; it helps increase visual awareness for future folks handling this item.
I added extra pieces of tissue as needed, including a final layer to make sure everything was covered. Then I tucked the edges in to create some support for the ends of the tube, a trick I learned from watching videos shared by the Museum of London as part of their on-going work.
The finished roll is MUCH more friendly to safely house - it's in an acid-free textile box with clothes of the same era, and safe from crushing or twisting,
I added a label in acid-free pen on the outside, and that was that!