Shall consist of red brass scrap, valves, machinery bearings and other machinery parts including miscellaneous castings made of copper, tin, zinc and/or lead. Shall be free of semi-red brass castings (78% to 81% copper) ; railroad car boxes and other similar high-lead alloys ; cocks and faucet ; closed water meter ; gates ; pot pieces ; ingots and burned brass ; aluminum, silicon and manganese bronzes ; iron and non-metallics. No piece to measure more than 12’’ over any one part or weigh over 100 lbs. Heavier pieces acceptable upon mutual agreement between buyer and seller.