I use a superpet/kaytee bath house personally, I know it's plastic but they have their bath toward the end of playtime and always supervised. then they get their hay rack and pellet bowl refiled and they know its time to go back. They also got used to associate the word bath with it and the sound of us shaking it and get exited when hearing it and stand waiting for it every time now. but yes a ceramic container would be good as it would keep cool so would be great on a hot day. On that note I have heard of some people putting the sand in a ceramic container in the fridge for a little while to make it even cooler, but I have not tried that as my fridge is a bit small and always find it a bit humid so I imagine wouldn't be good for the sand.