When we had hamsters, I used Aspen shavings most of the time until I discovered Carefresh. Sandra and I discussed this one time because she didn't like it and I did. I think the difference was the size of the animals. She has Guinea Pigs. Perhaps it is best used for the smaller ones like hamsters. I never had any of the problems she experienced with it.

When I got my birds, the petstore said use corncob in the bottom of the cage. I bought it. Then one of the first things I read in my Cockatiel book was to NEVER use corncob bedding! I didn't like it anyway because it did get moldy very quickly. Now I used newspaper as the liner in the cages and when we built the nest, recently, I used Carefresh in it.