What to put on bottom of cockateil cage?

If there is a separate bottom in the cage under the bottom grate, there is always newspaper. If it doesn't have the bottom grate, there is a product made from ground up corn cobs. another product is compressed pellets of sawdust. this is more for rodents. A new product is thin strips of paper but I find this messy. The corn cobs are probably the best and if they eat it, it is no big deal.