Here’s a tip for simplifying the clean up of dry, fine materials. Put a smooth cloth down under the item, such as a Tenebrio beetle container or a tabletop sensory box. Use a cotton cloth that is larger than the container, perhaps a tablecloth—large enough so it covers the table or children can sit on it around the box on the floor. Any bran or sand or rice that spills can be contained by the cloth and transported to a trash can (or back into the container if still clean).
A cotton cloth will not become as charged with static electricity as a synthetic or silk cloth, so particles such as bran or feathers will more easily fall off when gently shaken over the trash can.
One year I used a white cloth with a realistic black insect print and some children were reluctant to sit on it! When a beetle was dropped on it, it became a lesson in camouflage.
Peggy