Fill an empty spray bottle with water. The temperature of the water doesn't matter.
Hold up a paper towel sheet and spray it with the spray bottle. You want the paper towel to become moist without becoming soaked. This is why it is important to use the spray bottle and not just put the paper towel under the faucet.
Drape the paper towel over the brand-new softball. Make sure it is also covering the bottom of the ball.
Set the paper-towel-covered softball in the microwave and set the time for 90 seconds on high heat.
Remove the softball from the microwave and set out overnight to cool off. Then use it as you normally would.