My collection is kept on paper towels. Daily checks and water/bedding replacement goes on. Once a month, unless needed sooner, the tubs and water dishes are washed down with dish soap and hot water and replaced.

My collection also gets weekly baths to both keep them smell free and to combat the impressively low humidity where I reside in southern California. Essentially I fill the bathtub with water halfway up the animal's side and let them swim around a bit, drink the bath water, and occasionally defecate and urinate.