Cardboard, is it safe? help.

[russian_hamsters]

Hi all, got a quick question to ask......

Is it perfectly safe to use cardboard in the cages? Ive just cut and made some small sleeping areas out of those energy light bulb boxes that we've been getting free through our doors in the post lately. Ive not used the actual glosy type boxes the bulbs them selves come in but, just the plain square cardboard boxes theyre posted it. Seems complicated but im sure some of you will know what im on about.

I did have some self made wooden houses in there, which i sterilized and cleaned, but they seem to be making the hamsters itch and scratch like crazy.......so ive taken them out and wont be putting them back in again.

Any advise or help will be greatly appreciated.

Thanks.