Bags Homemade RattyRat's Review: Bags of all kinds can be great fun for your rats. You can use grocery bags (without much printing), lunch bags, cloth bags, what ever you can find or pick up for free. What's even better is if you fill the bags with stuff for your rats to crawl through, such as shredded or crumpled paper, corn starch packing peanuts, clothing, anything that is rat safe to chew on. As they get dirty, simply throw away the old ones and replace them with new ones.