There are many different things that guinea pigs like to play with or chew on. They like to chew on wood so if you have some clean pieces of wood that would work. They also like cardboard so empty toilet paper rolls could be another thing to give it.
Paper towel rolls stuffed with hay, the tubes that UPS sells for paper work saw it in half and they can run threw it. Boxes but take tape off and mine love baby rattled they flip and toss them in the air