A few weeks ago I bought a pack of Cellulose Sponges. I want to use them to wipe off the cages and clean the birds' toys and dishes and stuff. It says on the back of the bag "Not for aquarium use" and I am wondering if it is OK to use on my birds stuff? Are they toxic at all? I really have no idea. When I took one out for the first time today, I started rinsing it in a sink and the water that was rinsing it was bubbly and looked as if I was squeezing out a sponge that already had soap in it.