I understood that newspapers use soy-based ink that is non-toxic. Also, it is hard to believe that corrugated cardboard contains ground glass--that would really mess up the the process of making it out of paper pulp. Kavykeeper, where is your info from?
A woman who is a member of our guinea pig rescue worked for a company that manufactured cardboard. She posted a comment on our forum. I attached her comment:
"I know I've said this before to the group, but I haven't said it in a while
>so I'll say it again. Cardboard boxes are not good for them....especially
>the heavier duty boxes, i.e. corrugated boxes. Corrugated boxes are the
>boxes that have the wavy medium between two flat liner panels. I used to
>work at a box company and believe me, you wouldn't want your little
>critters chewing or eating that stuff. It can contain all sorts of things
>like glass or metal shards, sand, dirt, etc. To make the wavy paper, the
>medium has to go through corrugating rolls. The junk in the paper actually
>wears down these steel and chrome rolls in a matter of 3 months if they're
>run constantly. The glue that they use to stick those boxes together is
>also dangerous. It's made out of starch that contains a good amount of
>bacteria. I would use extreme caution when using boxes since it's a box
>maker's job to make a box, not worry if the box is clean enough for pet
>use. Just FYI."