When it comes to choosing a shower curtain, a nylon one is the greenest and easiest choice. Unlike fabric curtains that need a plastic liner, nylon curtains are naturally water-resistant and do not need a second liner. But they are also greener because they don't off-gas the way old-fashioned PVC shower curtains do. Even better: Unlike PVC, which is not recyclable, nylon shower curtains are recyclable and can be made into new products, like carpeting, string and fabric.