containers called stufas: round, vented tin or copper containers with shelves that held the pizzas apart from one another. Since the 1940s pizza take-out was done with the pizza sitting on a round cardboard base and covered with a paper bag. It is believed Domino's developed the modern corrugated flat square pizza box in the early 1960s, but they never patented it. Patent designs for pizza boxes date to at least 1968. Innovations since have included various venting configurations; built-in holders for extra sauces; designs for easier recycling; and perforated tops so wedge-shaped pieces of cardboard can be used as plates. The lid of the box is often supported by a disposable plastic tripod on top of the pizza known as a pizza saver. Pizza boxes have a large amount of corrugated fiberboard, individually and in total volume produced each year, but they are not accepted by some municipal recycling programs because the cardboard is often soaked with grease, making them unsuitable for some forms of recycling. Boxes may thus be commonly thrown away with household waste into landfills; a more environmentally friendly disposal option that has been proposed is a form of composting for pizza boxes. It is also possible to tear off unstained or unsaturated sections such as the lid and/or sides of the box and recycle those. Pizza saver In 1985 Carmela Vitale was issued a patent for a plastic 3-legged tripod stool that would sit in the middle of the box and keep the top from sagging into the pizza. Vitale called her device a "package saver" and used that term also as the title of her patent, but it has since been renamed the "pizza saver". Variations on the device have since been invented, such as a disposable plastic spatula whose handle holds the box top up; and a plastic tripod like that made by Vitalie, but with one of the legs serrated like a knife, making for easy cutting of stuck cheese and bread. Employment In the United States, two labor unions have been formed specifically for pizza delivery drivers: the now-defunct Association of Pizza Delivery Drivers (APDD) and the American Union of Pizza Delivery Drivers (AUPDD). APDD was formed in 2002. Its initial claim to fame was as an Internet-based union, eschewing traditional methods of organizing, and making contributions and the sale of goods the center of its fundraising activities, instead of dues.