Chins can also get bored with toys, it's good to change them out/rotate them regularly, like you would a dog. Take the old ones out (put them aside if still good) and put new ones in (or old ones you took out a few swaps ago) a few times a month.
Paper towel rolls are ok, so long as it doesn't have any glue on it, and so long as your chin doesn't eat cardboard. Most chins just chew up and shred cardboard, but if swallowed it can cause a blockage in their gut.