I took the chance to consolidate all my nuts and bolts into a few compartment organizers. Hands down, the best I have found are the organizers made by Durham who OEM’s the Fastenal organizers.
The only different between buying from Fastenal or Durham directly is the color (Gray vs Blue).
What makes them amazing is that they are made of all metal; the compartments are made of heavy plastic dividers, and when you close the lid, it seals every compartment completely. I have M2 inserts in on my organizers and even those tiny pieces do not move compartments when I shake the box around (including flipping it upside down and sideways).