Remix: https://www.thingiverse.com/thing:3912997

Using xyzaidan's method I made a mold for producing small cardboard organizers. The material was perfect for this application, I'm impressed how durable the boxes feel even with such thin walls. The holes are appropriate for 8mm carriage bolts since that's what I had on hand. Be careful to get the orientation of the lid right, pressing it in the wrong way will create noticeably lopsided walls. I marked the matching sides with tape on mine.

The plan is to coat them in shellac to maintain the biodegradable nature of the project while providing some protection from water. I attempted to speed up the drying process by placing the mold in a 150F oven, but after a couple attempts the plastic has started to warp. If you want to try it at lower temperatures then make sure the mold has had a night to sit and the clamps are off.