what kinds of cardboard is safe to use?

[fluffy nibbles]

We have a syrian hamster pup and we were wondering if we could use cardboard tubes and boxes for him to play with in his cage?
I was thinking about a pringles tube but i am concerned the inside of this would be unsafe for him to chew on.

[Iluvhamsters]

I use things like empty cereal boxes and other boxes that food comes in, toilet roll tubes too. Pringles tubes should be fine, there are quite a few people on here that use them

[fluffy nibbles]

Cereal boxes aswell !!, thankyou thats really helpfull

[gellerbing]

i use tassimo boxes and toilet roll tubes