newspaper would be fine...the packing tissue/newsprint used to wrap delicates and breakables. Heck, break down a cardboard box or two and line the cage with that. Just make sure any tape or stables are removed.
A couple green garbage bags, taped at the corners would be fine as well. If you really want to use something like paper towel, you can use toilete paper or kleenex.
A couple of thin clean rags would do as well. An old bed sheet would work, just make sure th ere are no freyed ends where he can get his feet caught in or try and eat.
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PHLdyPayne