Wool puddle pads are very popular, and for good reason. You can place this single sheet of wool on top of a waterproof mattress and under a cotton cover sheet for added protection against leaks and messes. It's easy and quick to remove a puddle pad after an accident and the pad can be rinsed and hung to dry as needed. This usually means you only have to give the waterproof mattress cover a quick wipe down to keep it clean. Because cotton absorbs moisture and wool wicks it away, it’s a good idea to combine a cotton pad on top of a wool pad to minimize the potential for wetness to penetrate the wool pad. Be sure to check that any wool puddle pads are 100% certified organic wool as some pads contain synthetic fibers. The two best options I can find are Holy Lamb and Home of wool.