I turned my old dirty play pen into a puppy pen for my four week old chihuahua puppies.
I covered the mat with black garbage bags and then laid down layers of towels, newspapers, and a top layer of fleece.
I change the top layer twice a day and I change the newspaper every other day.
So far the fleece does a great job of catching all of the puppies waste.
They do however enjoy spilling their water all over which requires a new change of all the layers.