Wait a day or so before you remove the Play-Doh from the airtight container. Peel the paper towel away – it should no longer be wet. Feel the Play-Doh: squeeze and pull it. Gauge whether it is soft enough.  If the dough still isn't soft, try adding more water and kneading it in directly. The Play-Doh mixture is mostly water, salt, and flour, so you might be able to restore the balance by re-hydrating the putty with enough water.  If the dough doesn't become soft again with repeated efforts, it might be time to throw it out. Consider buying or making new Play-Doh.
اتركه ليمتص الماء طوال الليل.