While plastic Easter eggs may not be the most eco-friendly invention, they are something that many kids love to search for in the backyard. But while it may seem eco-friendly to buy secondhand eggs from a thrift store, you might want to think twice. In 2008, a study was done on randomly purchased plastic eggs, and many of the eggs had high levels of lead. Since you can't tell if the lightly used eggs you buy have lead or not, they could pose a health risk. If you do buy used plastic eggs, fill them with wrapped candy. Better yet, just dye real eggs using natural dyes. Whenever you can go plastic-free, it's better for the environment.