One advantage of such material, though, is the opportunity to view droppings on a continuous basis. When eaten it also expands greatly when in contact with the moisture of the digestive tract easily causing impaction and subsequent death. There have been reports of death through impaction in birds that have not been near the substance in question for many years as it is retained and not passed. So far, it seems there is NO good choice. After listening to the opinions of many vets including several avian specialists, the universally recommended cage liner is plain old newspaper.
Newspaper is inexpensive, easily changed and allows for easy viewing of droppings.
Several layers can be cut to size and rolled up at a time for quick clean up, leaving clean layers for later. True, newspaper is not very attractive in the bottom of a cage costing several hundred dollars. If appearance is important, many newspapers give away the end rolls, each containing many weeks worth of paper. This same paper can also be purchased from paper vendors very inexpensively. For small cages, paper towels or butcher paper can also be substituted, both being more attractive and still fairly economical.