Be verrry careful of boxes with coloring on them (soda boxes, cereal boxes, etc.). While most dyes used in those boxes is now soy-based (as is the case with newspaper), it is probably safe, but I never wanted to risk the chance. I actually used to call the companies to see what the ink was made from to be sure that it was safe. I found out that most cereal boxes were not made from chin-friendly ingredients, but most pop boxes are safe. As with anything, if you notice them ingesting too much of it at any one time, take it away and let them have a break. My chins really did like it when I cut up paper towel or toilet paper rolls, into sections about 1/4" thick. That way I knew they weren't overdoing it in ingesting the material.