Notebook pages can be recycled via standard paper recycling. The play features large puppets made out of recycled and reclaimed materials. Most flammable materials can be recycled into industrial fuel. Cardboard can be recycled for industrial or domestic use. This material combined recycled fibers with virgin wool. Rebar, like almost all metal products, can be recycled as scrap. Where available, Roman brick and stone buildings were recycled for their materials. Waste oil from deep frying is increasingly being recycled and refined into biodiesel. This scrap is recycled by remelting it. Some hazardous wastes can be recycled into new products. Many hazardous wastes can be recycled into new products. Currently, only 9% of plastic is actually recycled. Upon failure, a catalytic converter can be recycled into scrap. Wax paper also cannot be recycled. As such, few are recycled and most end up in landfills.