Packing Peanuts

They're made of corn and dissolve when wet but are not made to be ingested even by accident. I would not use these.

A safer alternative is a box full of plastic mini wiffle balls or cat balls. I saw large pom poms used for a rat dig box on Pintrest.

🤷‍♀️ All compostable/ biodegrable packing peanuts are made of plant derived starches to be environmentally friendly. Corn is the most commonly used for packing peanuts. Wheat is another but I don't know if that's any safer for accidental ingestion.