Cook the Baseballs
If you live in an arid part of the country, you may be able to dry the balls by leaving them out in a dark place, such as a garage. Placing them in direct sunlight will shrink the hide of the ball, giving the ball a harder, papery feel. Or you can heat an oven to 180 degrees. Place the balls on the middle oven rack and bake for four to five hours. Baking them at a relatively low temperature will prevent shrinkage.