While disposable plastic cups are never really an eco-friendly option, sometimes it's hard to avoid the choice for special events or get-togethers. If you must buy throw-away cups, choose ones marked with a "1" recycling symbol on the bottom instead of the standard "6." No. 6 plastics are typically found in Styrofoam or dense plastic cups designed to mimic crystal. When the plastic is heated, it can release toxic chemicals. No. 1 plastics (made of polyethylene terephthalate, or PETE) are found in soda and water bottles. The plastic is relatively safe, and it's the most commonly recyclable plastic. So when your party is done, you can toss the No. 1 plastic cups into your curbside recycling for safe and green disposal.