The present invention provides moldable compositions that are capable of drying and hardening if left in open air at room temperature for a period of time. Embodiments of the moldable compositions comprise water, at least one polar polymeric resin (e.g., polyvinyl alcohol), at least one thickening agent (e.g., boric acid, borate salt, or hydrate of a borate salt), at least one humectant (e.g., glycerin, propylene glycol, etc.), at least one filler (e.g., corn starch, tapioca, or arrowroot), optionally at least one releasing agent (e.g., mineral oil) and optionally at least one additive.