Don't use plastic sandwich bags when making a ham and cheese sandwich for lunch. Instead, choose from three options (ranked from greenest to easiest): a hard-plastic lunch box, wax paper or aluminum foil. The lunch box is reusable, but if you're forgetful, you'll probably lose it. If so, then wrap sandwiches in biodegradable wax paper or recyclable aluminum foil. All are good choices; just do what's easiest for you and best for your PB&J.