The stool is soft and since they walk all over it, it has smooshed into their wheel, on the tiles I have by their food and the tiles I have on the top floor for them. It has hardened back up and stuck to each surface. This is the second day that this has been happening, I took out their pellets before I left for work today.
I do know that their hay is peed on each night by one of them, I have tried to stop that by putting the hay in a container, that hasn't stopped them but every morning and night I dump the hay out, wash the container and put new stuff back in. However, where I am living we have had a very muggy humid and damp summer so far so that could be coming into play as well as unfortunately things eventually get damp no matter what you do in this kind of weather.