This gray, self-hardening modeling clay is prepared in moist form, ready to use for all methods of modeling, including wheel throwing and sculpting. When completely dry, finished pieces are durable but not waterproof. Knead MarblexTM to increase plasticity before modeling. Keep unused clay in a plastic bag or wrapped in damp cloth to prevent drying out. It will shrink during drying, so it is best to hollow out bulky sculptures or wrap a slab of clay around a loose crumpled paper armature before modeling. Allow the finished piece to dry slowly and evenly on all sides at room temperature and away from heat until hard. When piece is completely dry, decorate with AMACO® Rub 'n Buff®, school paints, temperas, acrylics or liquid crayons. After decorating, it is a good idea to coat with shellac or varnish to seal it and make it water resistant.