Sometimes when I'm looking for a specific color of clay I find that the clay is a few years old. In order to use this old clay, I must bring the clay back to a soft, flexible state. To do so, I chop the clay into small pieces, add a few drops of baby oil (mineral oil) to the chopped up pieces and then squish them back together. Next, just roll the clay out, squish, roll out again, repeat until the clay is conditioned.
Another way to condition clay is to warm it up. Take hot water in a pan and set aside. Place your packages of clay into a ziploc bag and place the ziplocked bag into the hot water.
